As far as I know...
Friendly makes the bot friendly to players and enemy to enemies.
Neutral makes the bot neutral, only engage players when attacked.
Also, I think bots who are not friendly have a chance to attack neutrals but don't quote me on that.
Enemy makes the bot an enemy of all.
Mercenary's a deathmatch team (according to Resonte at least)
Owner teams the bots with the brick's owner.
Custom is used so you can have separate Enemy teams. Also, Slayer allegedly has compatibility with this feature to ally bots with teams of the same name but this is yet to be confirmed.