I think it would be pretty cool if you could do trading with other players, or some kind of interaction between teams. Just something that makes having separate teams a bit interesting. Research cooperatives or something. Sorry if I'm not really giving concrete suggestions but I think more team-to-team interactions would be cool would be interesting.

Lastly, is there any way you can make it so each team can toggle biters on their own worlds when making a team? Me and my friends have this one world with MTS and some of us like having biters on while some of us just enjoy the factory building. Would this feature be possible?

Just come up with something to add on top of the biters toggle, maybe you could add a feature that allows you to set a grace period before biters actively attack if you toggle the biters option.

I will look into it.