If WW II had not happened, could the 1939 Plan for an independent Palestine for both Jews & Arabs have worked?

No, both the Jews and Arabs were over promised. There was bound to be conflict. I don't think it is an accident that many of the countries that were given their freedom or land back are now in conflict and war. Israel/Palestine, India/Pakistan, etc. etc., and guess who profits from their conflict? The countries that did the splitting. Coincidence?