The population of Jordan is about 50% Palestinian. Most of them were either war refugees from Palestine or their descendants. The idea of a confederation of the West Bank with Jordan was tossed around but it didn't pan out. In line with the Oslo agreement, King Hussein renounced any Jordanian claim to the occupied territories in favor of a separate Palestinian state.
If you are going to hang your hat on the Oslo agreement, then why do you seemingly dismiss all of the violations of that agreement that have been committed by the PA in the years since? You seem to want to force Israel to live up to that agreement line by line, but give the PA a free pass to disregard any and all of it except for cherry-picking the parts that they like. Sorry, that is not how the world works...