H.W.
If it were me:
I'd keep my head down, keep doing the good work I could, and steer clear of the troublemakers. In regard to the group who wants to start a new school: I would NOT commit myself to any one group or the other, vocally, but stay open to receiving information about the new school.
Consider this as an opportunity to model for your children a very important skill;"How to deal with difficult people". Sometimes, ignoring them and going about your own business is a great option. I also think parents can work at a very grassroots level to solve problems without the assistance/permission of the board of parent volunteers. If they are incompetent, find a team of two or three other competent parents to organize and get things done which are important. Not every project needs a ton of discussion/nominations/motions before going forward.
If the incidents which trouble you are not affecting your children directly, I'd say stay where you are, see what happens with the new school, and once it's open, decide from there.