all good points
Hamas is not even Hezbollah's (Lebanon's) most significant ally in Gaza.
It is instructive, as you point out, to understand that Palestinians are welcome nowhere outside of Gaza and the West Bank. Certainly, Jordan, Lebanon and Egypt want no refugees, as you think they might accept in such times of war.
Israeli Palestinian policy has been very wrong since the formation of Hamas. Israel has continued to fight against a Palestinian state, fearing such a state even more than the Arab countries where they have caused civil unrest. Israel helped Hamas a lot over the year, giving aid through Qatar. The idea was to weaken El Fatah and the Palestinian Authority. This error has had horrible consequences.
Perhaps, just perhaps, after this war (even with some foreign participation), there can come the realization that the Arab states need to guarantee peace and security in Gaza, not Israel. Israel must WITHDRAW from the West Bank, as they did from Gaza, with all settlers leaving the West Bank. Israel did it exactly backwards in the past in withdrawing from Gaza instead of the West Bank. The sticking point, of course, is the administration of Jerusalem. Clearly, the solution will require the finalization of the agreement between Israel and Saudi Arabis, obviously after there is a new government in Israel, and the beginning of the dismantling of the settlements. The mistake must be corrected. The Palestinian Authority is the answer, no matter how unpopular they are at the moment (unpopular because they are corrupt and can't stop the Israeli policies in the West Bank, including Israel allowing all sorts of crimes by the settlers.