I do believe that the reason why the Habsburgs were able to consolidate their German (and Bohemian, Hungrarian etc...) holdings were because lil Max was essentially the only Habsburg male with any descendants at the time. Otherwise Tyrol, Further Austria, or hell even Bohemia and such might have the danger of getting separated from the "core Habsburg" lands. i mean it wasn't so long ago that dear old dad Fred was at throats with Ladislaus the Posthumous for some land
So there would possibly be a rivalry between the main line and the Swabian line? Makes sense. They might have divergent interests with regards to Germany, since the Habsburgs have now got Burgundy, Bohemia-Hungary and Spain on their plate as well as Germany. Love between the two branches might have to some times be forced in order to get them to move in lock-step. I wouldn't be surprised if young Fritz attempts to marry Margarethe of Austria between her first and second widowhood, and Maxl arranges her marriage to Savoy in order to prevent this, for instance.