AI is working a little weird for battles.

so i have my castle set up, just getting started. i have a stone wall out front, there are two houses which my main ranged guards stay in, the roof is a place where they can shoot arrows from till the enemy breaks in. 

i set one of my archers up top to watch out for the enemies, and locked my doors.  she is set to ranged only.  enemy closes in, she sets off a few shots, then jumps off the roof passed the palisade and out of my locked gates right in to the middle of 5 enemies, i use her to kite but because she isnt my leader its not really that effective, of course she dies i try to stop it with my leader and jump into the fray only to be friendly fire shot in the head 3 times by my own people.  is there maybe a way we could get a FF toggle i understand theres skill and some realism involved but if it takes 4 shots to hit a target minimum it doesnt make sense that everyone would target the same person and hit all at the same time.

it would also be nice if the defensive items and buildings worked/were explained better as to what theyre supposed to do.