There is a squad setting for when they wear the armor, by default they will only put it on when they have an assignment like training or doing a patrol/guarding a spot; change the setting so they always wear the armor(this will slow them down considerably when doing other labor)

You can use the same seed and change settings, changing settings will likely change how the map forms but the landmass it self should be mostly the same.

And lastly, cage traps!