His uncle, Jodokus, Margrave of Moravia would most likely succeed in Bohemia and the Luxemburger lands. The Empire is anyone's guess, since the Bavarian party was reasonably strong in the reign of his father, and Henry IV of England seems to haveconsidered the Wittelsbachs the horse to back when marrying his daughter off (or perhaps that was simply due to the house of Luxemburg's alignment with the Valois).
As to the Hungarian throne, IDK how the inheritance would work. Jadwyga already had the throne of Poland, and I doubt they would countenance another PU. Next up would either Laszlo V/le Magnanime of Naples (who seems to have claimed the throne after Lajos I's death) or his sister, Giovanna, who became queen in turn. Of course, Jadwyga might decide she likes Hungary better than Poland and the Poles have to pull another prince out of a hat.