RE: what rampant dose other then AI things, that is combatable with this mod?
The all AI things should be compatible when you use biters and its variants as 'enemy' force in your game. If you don't use biter faction, you don't need to enable rampant, it would be waste of performance.
If you want to modify to work with zerg or other custom races, you'll have to dig its lua files on how things are handle and test them. You may only need to change things in Upgrade.lua, since that's where I see various queries are targeting 'enemy' force. My custom races use 'enemy_{race_name}' format. e.g. enemy_erm_zerg.
RE: something i love to bits is having my bitters fight each other. is it possible to set the different 'factions' to be enemy's?
lol. Yes. It's possible. A new command will be add to enable free for all mode in next release.
For current version, you can run the following command to disable their friendship.
/c game.forces['enemy_erm_toss'].set_friend('enemy_erm_zerg', false)
/c game.forces['enemy_erm_zerg'].set_friend('enemy_erm_toss', false)
However, you should only play with max level 5 or max level 10 enemy for this. They don't have enough damage output to kill each other in a reasonable time at higher level. The spawner will spawn unit faster than they can kill each other. This end up lagging your computer till one race kill off the other one in a huge war.
RE: do the 'enemy settings' (on new game creation) effect the newly added factions?
Yes they do. All settings behave the same. Having higher factor values will speed up the level up.