Hirelings already have no friendly fire. In fact, friendly fire isn't a thing in most parts of the game. The only exceptions to this are Playground Mode, where enemy squads can friendly-fire eachother, and explosive/splash damage weapons, which can friendly-fire regardless of who's using them.

As for making Hirelings able to walk through eachother with no collision - they already have the IncorporealFaction trait. That trait is supposed to allow characters to move through allies without colliding with them, but it doesn't appear to be functional and I have no idea where I'd even begin to go about fixing it.

Actually, when the hirelings do that weird thing where they get mad and rush for the enemy, they CAN hurt and even KILL me or the other hirelings.

Ah, The bullrush charge attack. Right, that. Yeah, I'll just remove that in the next update, I've had a similar issue in my own playtesting and it seems to be doing more harm than good.

yeah, that was a annoying skill. probably from merc zerker's animation