Austria Hungary was facing massive problems among other things ethnic violence in Galicia and the istrian cities, starvation in Vienna, the Hungarian aristocracy withholding food, troops and taxes from the other half of the empire, the army an especially the officer corps utterly gutted by the Russian front, the army itself demoralized, disorganized, the navy impotent and having lost a major battleship to a port raid, among many many other things.
Because of the war, if you end the war the situation will improve.
In all probability you'd see 90s Yugoslavia style violence and ethnic cleansing, with Germany having to step in (and probably picking sides, and generally exacerbating the issue).
If the Austrians and Hungarians are not tied by foreign pressure like OTL they can keep order as soon as the war ends. If Germany chooses to make the same choices of USA IOTL they certainly are going to make the place a huge mess.
If nothing else Galicia is going to try and jump ship to unite with Russian Poland and that's going to trigger Ukrainian uprisings in Lviv.
They can try, doesn't mean that they have enough power to do so on violently and on their own. Without someone like the USA breathing down the neck of Austria and Hungary, it will be better to the polish if they don't take extreme measures, but I can see Austria letting Galicia-Lodomeria go away if they are given economic compensation and territories in the south.
That aside, you get a separate Hungary and possibly a separate Croatia, neither of which has any reason to be anti-German
You took Croatia from Hungary, that is enough to piss them and make them say "come get it". By the way, how are you going to divide the Hungarian territory? Are you giving Transylvania to Romania? Keeping it in Hungary? What about Banat? Vojvodina? You aren't going to have a stable situation after the thing is done because all those countries are going to develop rivalries with each other based on ethnic and historical reasons, and those rivalries could even be exploited by other powers. Instead of your previous Junior partner completely tied to your interests now you have a quagmire of small states with the same ethnical problems that Austria Hungary had before.