Luckily for us, this event comes with dedicated farming maps, which have more checks per route than other maps, along with the ability to planning mode them.
Agent 416 Multitool
This Echelon works for all routes, although the requirements are a bit stiff. You need an Agent 416 from the Division Collab, and all 3 of her unique Equips, and then 3 HGs. While the HG requirements are less demanding, you will need some significant Damage boosts, and to position everyone correctly.
This Echelon will adversely effect your heart health if you watch the fight against the Beans. Your Dolls are in fact safe, but can leave the Beans alive for a little longer than you could like.

HG selection here is focused on Damage output over anything else. For this reason, P22 is highly encouraged, as are Python, Deagle, Contender, Jill Stingray, Grizzly, or Nagant Revolver Mod.
Agent 416's 3 Equips are very important, as they preplant grenades that clean out massive chunks of enemies immediately at the start of battle, including the Jaegers and Nemeums on the P22 and SL8 routes. A416's position ensure the bulk of the enemies eat her mines, as it spawns directly in front of her.
P22 Farm
We'll start with the hardest route first. Farming P22 on EX is a brutal exercise in upfront DPS. The Witch Dragoon nodes spawn Jaegers extremely close to your Echelon and they are almost immediately able to fire on your Dolls.
With 39 AP and roughly 60 Damage, these must be eliminated immediately otherwise they will tear your Echelons apart. These routes will use 5* Fairies to avoid taking too much Damage, and will frequently need 4 or more T-Dolls to safely farm.
General Recommendation

Kord/3HG
This is exactly what it says, Kord and 3 Damage Boosting HGs. Ensure Kord is set to Forced Manual to exploit her Peirce to insta-kill the Jaegers. The HGs don't matter too much to this, but Damage boosting is very important. Deagle/Python are both good choices for this as is Nagant Revolver Mod.
Kord/Python/Nagant Revoler can farm this route as a 3 Doll Echelon but you will be risking chip Damage.
SL8 Farm
General Recommendation
SL8's farm is generally easier than the P22 farm, without the Jaegers immediately in your Echelon's face. the Nemeums farther back can hurt quite a bit, but RFs and Kord can gun these enemies down efficiently. ARs not named 416 Mod or Agent 416 are not recommended here, but you should be able to experiment with rifles as you wish.
Kord/3HG
This is exactly what it says, Kord and 3 Damage Boosting HGs. Ensure Kord is set to Forced Manual to exploit her Peirce to insta-kill the Jaegers. The HGs don't matter too much to this, but Damage boosting is very important. Deagle/Python are both good choices for this as is Nagant Revolver Mod.
Kord/Python/Nagant Revoler can farm this route as a 3 Doll Echelon but you will be risking chip Damage.
Rico/Grape
This Echelon also has a bit of a stiff requirement, including 416 Mod 2 and Rico, a Gunslinger Girls collab. Her early mini-nuke shot is essential to mitigate the damage taken, as well as her tiles reducing P22's ICD. 5 star Beach, Shattered Connexion's ranking Fairy, is also a must-have.
Note that Rco had her SPEQ at +6, Grape had a +7 cape and 416 had her EOT SPEQ maxed while her Mod SPEQ was not equipped, higher enhancment levels on equipment may improve performance. A VFL may replace her SPEQ EOT.
CZ2000 Farm
General Recommendation
CZ2000's route is fairly straightforwards. You have more options to handle this one, including 416 Mod's Grenade, Rifles, and ARs in a pinch. Agent 416 and 416 Mod once again shine here. As the arguably easiest EX-farm, you will be in a better position to experiment with your Echelons.
Rico/Grape
This Echelon also has a bit of a stiff requirement, including 416 Mod with her Singularity SPEQ maxed and RIco, a Gunslinger GIrls collab doll. She is essential to this farm, as she both reduces P22's ICD and has an early nuke that mitigates possible damage on P22 on Bride node. Lastly, 5 star Beach, Shattered Connexion's ranking Fairy is a must-have.
Note that Rco had her SPEQ at +6, Grape had a +7 cape and 416 had her EOT SPEQ maxed while her Mod SPEQ was not equipped, higher enhancment levels on equipment may improve performance. A VFL may replace her SPEQ EOT.
There are doubtlessly other teams that can work for these routes, that either we did not test, or did not think of. If you have something that works, feel free to message Soulmuse#8741 on discord, or find me in the community Discord, and I'll see about potentially adding it here.
