You all are assuming that Louis II of Bohemia and Hungary will go as OTL. It doesn't have to end so - there may be continued Jagiellon presence in Bohemia nad Hungary. And if Jagiellon line dies out in those countries later, it shouldn't be assumed that those lands will automatically drop into Habsburgs' hands. The Polish Jagiellon line may decide to go for them...
Well we have a lot of possibilities here. The Burgundian inheritance is in retrospect likely to be the primary focus of Charles because of its wealth relative to Austria itself. So a conflict with France will be in the offing because of their opposing interests there and in the North of Italy. He doesn't have the wealth of the New World but he is likely still to be Emporer...
Perhaps a trade off is possible to confront the Turk....
Milan for the disputed terr. in France itself. Mind you I think Milan is still more valuable to both parties here.
Spain is likely to concentrate solely on the American empire and Italy and the Mediterranean, perhaps West Africa? They can partner with either France or The Habsburgs, whic hever is likely to be most beneficial to them.
Ferdinand, perhaps King of Bohemia and Hungary, if Louis is not killed at Mohacs. Will he be more involved with events though in Bohemia and Hungary given that Charles is likely to be totally focused on Germany and the Netherlands. He may even be at Mohacs with an Austrian contingent to support his father-in-law. Though, perhaps not.
But Tizoc is correct in that the sequence of events leading to Mohacs could well change simply allowing Louis to survive the encounter. Perhaps the Hungarians do not even engage the Ottomans there. It was afterall not the preferred option of Louis anyways.
So there is a wide scope for divergence here with a continuing Trastamara Spain. Which personally I have always rather liked.