riflemen defenses mines are currently bugged, so they aren't very useful now. And spamming fighting positions isn't usually a good idea as they are easily countered. you get maybe two at most.
Infantry company allows you to be a bit more defensive then you usually would, but at the end of the day it's still USF and you have to be aggressive.
Bugged how? All I saw using them was it was low damage, but I didnt see if enemy was clumped or spread when the squad tripped the mine.