As for Austria-Hungary; well, my course of events is not neccesarily the most likely outcome, which problably would involve some sort of absorbtion of the Austrian part of the Empire by Germany. On the other hand, OTL's history doesn't always take the most plausible route either!
I freely admit that I've got a bit of a soft spot for the Hapsburgs, and in this TL they do roll quite a lot of 6's in the critical inter-war period (the incompetence of the Hungarian rebels is one example of this-although personally I think that given the people I've got involved in it a degree of idiocy is inevitable). On the other hand, OTL it took 4 years of appalling warfare and hardship for A-H to collapse- here it has a short although occasionally embarassing war, with none of the food shortages etc that took place in 1914-1918. I agree things have to come to a head sooner or later, but the way I have them happen removes the largest single obstacle to reform (i.e Hungary) for long enough that it has to accept the post-1925 fait accompli.
In this TL I expect the success of the Hungarian revolt would be a popular PoD though, especially if there's a feeling that the new Hungarian state might align itself with the Russians.