So, if we don't determine who rules Palestine, how do we remove the currently in power party and also any future parties if they happen to be insufficiently homegrown to our standards (the funding aspect)?

The entire conflict is that Israel believes their safety necessitates that Palestine not be sovereign because they believe a sovereign Palestine will try to take back the land it lost whether in Israel itself or the various illegal encroachments over the years. Palestine on the other hand is not going to accept Israeli sovereignty over it. And thus the conflict. However many or few foreign actors are involved doesn't change the root of the conflict.