how do you play with this AI you speak of? I saw no such setting.
You just go into nearby or far away (I recomend far away if your at home or around Wi-fi so someone else can join you) and create a room then you can play with bots instead of waiting in the practice room (I know, the practice room is pretty much pointless since you can do that but its more fun atleast)
And I didn't know you were allowed to choose your team.
Yeah, I may be wrong about that. I think its just on friend matches you can.
Also, question that's been bugging me... there's no friendly fire in light vs dark, right? I keep getting paranoid that I'm shooting my own guys...
Nope, its like TF2 where you can hear the sounds of you bashing your teamates head in with a shovel or bat. But they dont really take damage (unless their the usual pissy 20 year old TF2 asshats then you deal emotional damage.)