Good luck to you. Coup d'etat isn't something everyone can say that they participated in. This will either work out well and you'll be high-fiving the remaining team—or you're all getting fired. Simple as.

FWIW, I've worked at places (plural) like the one you've described. In my experience, "reading the writing on the wall" and focusing on my resume and marketability (in preparation for leaving) was "the move". I burnt no bridges, even when I really wanted to.

If the team is so amazing, you should probably rethink firing the dude who formed it. Why don’t you guys start your own company?