Strategies are obviously somewhat different in multiplayer from the solo runs. For starters, you have the choice to use different classes and take advantage of each class's abilities.
DLC 2-13 The Last Stand 2
1 Air Raider - Combat Bomber KM6 Plan X18, Absolute Bunker DZ, ZE Blaster, Nix Assault
other ARs - Combat Bomber KM6 Plan X18, ZEXR or Combat Bomber KM6 Plan Z4, ZE Blaster, Nix Assault (or Barga to be a decoy)
Bunker to help all survive at the beginning, X18 is awesome due to the large number of silver spiders, ZE Blaster works nicely in open spaces. Z4 only really good against tadpoles, deroys and drones, but will wear down others too.
1 or more Rangers - Blazer and Buster Shot, Hybrid Protector XE
Blazer is very good for deroys, transports and blue tadpoles, Buster is exceptional for anything near, particularly silver spiders.
Wing Diver - Dragoon Lance ZM, second weapon Rapier to handle few enemies in close combat. Gleipnir is another option, it won't kill anything but will break most enemies' movements and attacks slowing them down.
Fencer - Dexter Automatic Shotgun ZGXE or YH7 Dispersal Mortar and Spine Driver MA, FGX High Altitude Impact Launcher and GX Arm Hound or Rapid Hound, Dash Cell G and Add Booster G
This mission has 5 waves and it's a bazillion times easier in multiplayer than solo. Incredibly it will even usually work with largely uncoordinated players. The only really important thing to handle is the red bees transport and the tadpoles, including 2 blue ones in 4th wave.
The weirdest thing about this mission is the transition between the first 3 waves and 4th wave. Supposedly it's 20 secs after all enemies from the first 3 waves are wiped out, but it's unreliable, and even the jp wiki mentions this. Anyway, it's important to leave the drone bomber alive, as it's the least obtrusive enemy on all 3 first waves, and take that chance to regroup to handle the 4th wave which is the worse.
At the start AR should install shields, and he and Ranger should handle deroys, while WD and Fencer should handle silvers. Drones are the least problematic enemies if you're inside the shields, so these should be the last. Again I stress that you should just avoid and ignore the bomber drone.
2nd and 3rd waves are "just" 30 gold ants and 1 heavy frog. A WD or Fencer on top of the future spawning silvers transport (front left from start) can aggro the enemies on these waves, so other classes can turkey shoot them).
Golds will spawn around the buildings beyond the rail overpass to the right of starting position. It's important to handle golds ASAP because during the 3st wave, 3 squads of NPCs will spawn around the right end of the rail overpass, and these will be very useful as decoys and help for the 4th wave. You can capture either the WDs or Fencer squads, or both, Rangers should be left there to die while annoying golds and tadpoles in the wave (or all of them).
Kill bomber, when grouped and shield protected under the red bees transport, which is the center one, and will stay around back leftish from the start position. When red bees transport opens, WD and Ranger should destroy it and falling red bees, better one class should destroy the red bees transport (essential) and another the goldies, AR kill golds and tadpoles around NPCS (tadpoles will take time to arrive) with X18, Fencer missile them. Fencer missiles will be awesome for blue tadpoles as it keeps them rolling around. Focus on killing tadpoles and the 10 dropped frogs (after the red bees and their transport of course). If you can drop the gold ants transport (right front from start). The silver spider one is the least problematic leave that for last.
5th wave of 12 giant enemies will spawn, including 1 gold queen ant, a red giant bee and a silver king spider, once there is just 1 transport or 5 enemies alive including transports. Five hugely armored War Bargas will come to help once you've killed 4 of the big enemies, so just handle 4 of them which is easy with the firepower of the players, stall for the bargas to appear and turkey shoot the big enemies left while bargas entertain and destroy them. Bargas will handle queen bees and king spiders, but giant bees are more problematic for them. If the silver spider's transport is not downed at this point one of the bargas usually stays on top of it, and will aggro silver spiders under that transport (and other giant enemies).
I already did this mission 3 times with randoms, it's amazingly easy when at least 2 know what to do.
DLC 2-12 The Last Stand 1
Strategy 1
1 Air Raider - Heavy Bomber Phobos Z Plan 4, Combat Bomber KM6 Plan X18 or Tempest ATS, Absolute Bunker DZ, Nix Assault
other ARs - ZEXR, ZE Blaster, Guard Post M3, Nix Assault (or Barga to be a decoy), Z4, X18 or X5 (X5 does massive damage to what hits)
Phobos to destroy scenery and break enemies, KM6 X18 to destroy hives and wreck other enemies (very viable here due to the sheer number of silvers that generate a lot of points). X18 is faster to come, so aim Phobos first if using on the same enemy / hive. Tempest is more powerful to handle hives, can handle pylons, can handle frogs and can kill the giant red bee, but it will be troublesome to use with more than 1 big guy in sequence. It's always unreliable too.
Be careful that 2nd AR ZE Blaster will reach gold ants spawning from nearest pylon, when buildings are gone.
Silver spiders will provide 1700 points for each kill. For comparison, red bees will give 90, a gold ant 150, a colonist 420 (armored or not) and even a queen ant or bee around 1800. So it's easy to see the importance of leaving a silver spiders nest for last if there's an AR with points-based weapons (X18, X5, Z4, Phobos, Spritefall (not good here...)).
1 or more Rangers - Blazer and Buster Shot, Hybrid Protector XE
These will be the main defenders, especially against small stuff. Buster Shot is excellent against silvers, golds and big guys if they get near. Blazer against frogs, bees and pylons (since AR won't be able to destroy them, except theoretically could using the Nix).
Wing Diver - Dragoon Lance ZM, second weapon irrelevant, but Rapier to handle few enemies in close combat. Gleipnir is another option used on a corner, it won't kill anything but will break most enemies' movements and attacks slowing them, and it won't reach the pylon and its gold ants. Raijin Limit Custom could be interesting but be really careful with it, it has a spread shot and you can hit several enemies or hives / pylons at the same time
Focus on near enemies with Dragoon Lance ZM.
Fencer - Dexter Automatic Shotgun ZGXE and Spine Driver MA, dual Maximum Disruptors or dual 35mm Cannon, Dash Cell G and Add Booster G
Fencer can be a going deep team mate dragging all enemies behind him while the others shoot them, but he has to be very good to survive.
The Fencer (and WD) movement isn't useful, especially while red bees are on the map. Focus on near enemies like the WD. He's still good in case something goes wrong (like the WD) to take a hike to the opposite corner of the map, aggro all moving enemies there, and come back to revive everyone else if necessary. Dual Maximum Disruptors can help with big guys. Mobility could always come in handy.
Fencer and WDs moving fast around the map will almost certainly mean the continuous death of rangers and ARs playing, as they can't escape. Even inside Nix Assault can become troublesome to survive as there will be enemies spread all over the map, and gold ants and silver spiders attacks in multiplayer do severe damage. So don't be selfish...
No missiles, no rockets, no aiming weapons.
Start by occupying one of the corners that have a pylon near it. Install shield, send phobos towards pylon, X18 dead center on bees hive. Destroy all incoming bees, ants and spiders, then stop. Rebuild and reinstall the shield, and get a Nix. Phobos should be used to clean the area around the stand position to make it easier to destroy coming enemies.
AR ONLY advances in the Nix and destroys next red bee's hive. Returns immediately to shield and rinse and repeat, destroy small enemies. Be careful at this point to NOT piss ANY of the dropped frogs. Rebuild and reinstall the shield, and get a Nix.
AR goes and piss a group of frogs with Nix. Handle them, and small enemies. Do this for all 6 groups of frogs, you can also destroy the nearest gold ants pylon at this stage.
With all 18 frogs dead, you can destroy the nearest gold ants pylon, if you didn't, then either the last gold ants pylon or the nearest silver spiders hive. If going for the 2 gold ants pylons you should change to the nearest corner to each of them, before handling them. Try not to aggro any of the big enemies that will spawn. The advantage of going for the near silver spider hive us that you can attack the Red Queen Bee later without aggroing small enemies.
Of the big enemies, the most dangerous is the Giant Red Bee, so focus the X18 and Phobos on her, and whatever else is necessary to kill her. Even if all big enemies will wake, AR will have a huge number of X18s and Phobos refills to use at will, the ranger(s) will help with what is alive.
After all this handling the last spiders hive(s) and / or gold ants pylon is a joke compared to all that happened before.
Some coordination is required, it's not possible to do this one just shooting around. There are no NPCs throughout the whole mission.
The mission is easy as long as you don't rush it and piss what you shouldn't have.
Strategy 2
1 Fencer - Spine Driver MA and YH7 Dispersal Mortar, Dash Cell 5 and Add Booster 5 but G's preferable
1 Air Raider - KM6 Z4, Phobos Z 4, KM6 X18 (or X5 or Vesta DA)
Ranger - CA90, Blazer, running enhancement
WD - Gleipnir ONLY used on corners, Heaven's Gate D10 for likely suicide missions to destroy nests, pylons and Queen Bees as alternative to AR destroying nests and Ranger pylons
A strategy that just requires a Fencer to run around the map, and revive teammates while they suicide since they can't keep up the pace with him.
The only problem is dealing with the 2 bees nests, and to a lesser extent the 2 Queen Bees. From the rest, he can simply run away.
Occupy one corner near goldies pylon, better the front left one, AR sends Z4 and X18 to the nearest bees nest. Both should be rebuilt, and use them again when bees are closing. Fencer runs away in the direction of the destroyed nest, hopefully almost all the bees are gone. Ranger should try to kill what he can, they will likely die. Fencer goes around the map and revives them, they kill what they can and die again. Rinse and repeat until all enemies are on standby.
Go to the opposite corner, rinse and repeat, if frogs wake up there's no issue now. Ranger should use Blazer to destroy when possible nearest goldies pylon. Fencer should start to YH7 or use other weapons to damage the opposite goldies pylon to the place where AR and other players are. Once most frogs and the nearest goldies pylon to AR are gone, Fencer can destroy the other goldies pylon.
If Ranger is in the corner where red Queen Bee spawns, installing CA90 around that area is smart. If not, AR should send Z4, Phobos, X18 (these in this order) over red Giant Bee, if CA90 is there use it too. If the other Queen Bee wakes up, there's no issue Fencer can run away from here and she's a lot easier to destroy. Fencer keeps doing laps and waking up team mates, they kill what they can, and they die. Destroy the nearest silvers nest, and leave the last one so that AR can gather points.
Fencer will do most of the job, but it's just running around. AR is essential for its huge destruction, and there are a bazillion points to be gained on each attack so they will replenish fast. Without him, taking down the silver King and Golden Queen Ant takes forever. Plenty of crates for Fencer to pick. Even easier with 4, with 2 ARs, or 2 Fencers to assure one doesn't die. WD will run out of steam behind Fencer. Fencer (s) needs to wait in each corner for enemies to aggro there, otherwise they can all be over them when he returns near the AR (and other players). Ranger can be slightly ahead of AR so that he has time to install CA90's, which will have more than enough time to rebuild on each Fencer lap.
Fencer must be careful using YH7 near-dead team mates, even dead they can be blown away to awkward positions and mess up the run.
Fencer can use YH7 to blast away and destroy Queen Bees if necessary. Don't try to use Spine on them, its range is lower than the Queen Bees attack range.
Boring but simple and effective. Even simpler with 4, particularly with 2 ARs. One should then bring a Bulge Z for pylons. Vehicles are irrelevant, they shouldn't get away from their position.
Running away players if more than 1 need to keep together so that enemies don't spread around each other, but on both.
DLC 2-10 Engage Alien Troops 2
1 Air Raider - 150mm Cannon ν Lapis, ZE Blaster, Absolute Bunker DZ, Nix Assault
Vulcan Cannon and 105mm Rapid-fire Cannon are dreadful idea here. The chances to hit multiple enemies are huge. ZE Blaster works well against Red Drones which are some of the worst enemies.
1 or more Rangers - Blazer and Buster Shot, Hybrid Protector XE
These will be the main defenders. Buster Shot is excellent against near enemies. Blazer against everything far.
Wing Diver - Dragoon Lance ZM, Gleipnir good against red drones. As I said for mission 12, Raijin Limit Custom could be interesting but be really careful with it, it has a spread shot and you can hit several enemies at the same time
Fencer - Dexter Automatic Shotgun ZGXE and Spine Driver MA, 35mm Battle Cannon or 38mm Rage Cannon, Dash Cell G and Add Booster G or Muzzle Stabilizer S
The strategy is similar to mission 12. Occupy one back corner, left one from start is better due to elevated terrain of the destroyed silos, which will make it easier to hit enemies over the sea, particularly the red drones with the ZE Blaster or Blazer. Lapis is very good to level terrain and destroy scenery.
The biggest issue is a perspective error and you can be hitting a flying enemy that is much further back than it seems, so traveling along the map left side can help to check if they're far from the back where the most dangerous enemies are stacked. You need to handle as many flyers first as possible, particularly red drones. You should piss just one, kill everything that comes along, then proceed. Ranger is probably better for this, or fencer, go near hit one, retreat ASAP to shields. Always rebuild shields. The biggest problem is waking multiple deroys, 2 or more with a few drones and heavies and the shield will be gone in a snap.
The giant deroy has a bazillion lasers, try to get him alone at the end. Deroy missiles from pods are very weak, they won't destroy the shield. Deroys and red drones like to travel near non-aggroed enemies only hit them if you're sure not to wake anything else, so using something like a 105mm or Vulcan on them is usually a really bad idea.
As in the case of mission 12 this is easy if you are patient and do things quietly and with care. If you piss many of them at the same time it's 99.99% sure game over.
Some coordination is required, it's not possible to do this one just shooting around without a ton of armor. The starting squad of NPCs can be captured or not, they will be wiped out pretty quickly anyway.
DLC 2-8 Engage Aggressors 5
2 or 3 Air Raiders - Combat Bomber KM6 Plan X18, ZE Blaster and Nix Assault
Since the mission has only silver spiders and they provide a ton of points you can almost continuously call X18s. If they're almost all upgraded they do good damage and ZE Blaster will help finish the last ones. Just be careful to send X18 slightly to the front of the Nix as if done on top of it, the center of the attack can destroy it.
As a third weapon, each one can bring a different one from Guard Post M3 or Zone Protector ZM, Cannon Gun DZ which works really well here and can kill silvers in one attack, ZEXR is underpowered but an option.
One can bring a War Barga but it will be crushed in a snap by the silvers.
Ranger - Blazer, Slaughter EZ or Buster Shot, plus Reverse Shooter X and Hybrid Protector XE.
May I remind you how dangerous it is to use the Buster Shot near teammates. You can kill them faster than a silver spider...
Wing Diver - Rapier plus Phalanx, and Mighty core or VZ Plasma Core.
Mobile, handle stray near spiders and pick crates.
Fencer - mobile, close combat loadout (Dexter Automatic Shotgun, Spine Driver MA, Jackhammer MA, Dash Cell and Add Booster).
Mobile, handle stray near spiders and pick crates.
The strategy is to stay in the startup area. Install turrets and start X18 festival when silvers are approaching. Since X18 is fast unlike Z4 in everything (coming and time to recall), it can be an almost continuous summoning of them. All waves except the last will be almost in a row.
The last wave spawns away from the furthest beach so it takes some time, so be careful and save X18 when there are few silvers around and definitely rebuild turrets. The last wave has a lot of spiders, but they won't all come at once so it can be done.
No explosives, you'll be together so it's a really bad idea. The Nixes have them, but it's a close and somewhat controlled explosion.
Tons of crates thought.