I agree that Mr.Gold is probably on his own side. I’m sure Regina will find a way to get most of Storybrooke on her side. Either with fear, or a bargain. But I don’t think it will necessarily come down to just three sides (if we count Rumplestiltskin). It will probably be much more complicated then that. Regina still has Belle over Mr.Gold’s head, so he could very well be helping her at some point.