They absolutely should not fire the coaching staff, and I don't think they will.
I still like Bradley. I'm far less sure about Fisch, but I think there is a high chance he sticks around too. I'm not sure if that's a bad or good thing. One the one hand, continuity for the younger guys is important, but on the other hand he's done some really questionable play calling this year. Ultimately though, I think the number of things breaking down on offense due to so many rookies will give him the benefit of the doubt.