I pretty much think you had all the most important issues in you post. Also the way you list it.
But for the debate, let me, address point 2)
Hitler could If he had prepered for it, have moved into balkan, soon after taking France. If Hitler had concentrated on Balkan, instead of planning the invation of Britain, then Yugoslavia and Greece, could have been seized maybe as early as oktober/november 1940, Thus these operations would’nt have been in the way of preparation for Barbarossa, and a cancelling of yogoslavia/Greece wouldn’t have been on this list.
Well, I don’t really think Yugoslavia was worth taking. Greece, however, could be considered more important.
Well, The Islands of dodecanese Rhodos, Kos & Kharpathos etc. were already Italian (booty from ital/Turk war of 1912).