@Gwrtheyrn Annwn
Feel like your voice could be used here.
Well, you asked for it (literally).
I'll start with the premise, the Augsliech (I assume you mean the 1867 compromise given the 1917 version was never enacted) breaking down in rebellion in 1917 after Franz Joseph's death as per OTL. There are problems with this, for starters by that point it is clear that A-H is in a life or death situation, lose the war and vultures will be circling. Nobody in the empire, apart from maybe the Italian areas, wants this. A-H falls and Galicia is annexed by Russia (who are of course still in the war at this stage), Serbia goes full Yugoslavia, something that is the stuff of nightmares for Hungary, and Romania comes into Translyvnia, again the stuff of nightmares for Hungary, at the very least. So a Hungarian rebellion in 1917 has one result, the dramatic hastened of Habsburg defeat and the immediate annexation of swathes of Hungarian territory by Serbia and Romania. Give me one reason Hungary would rise up when that is the result? The only scenario I can see for a Hungarian rebellion is one incited by the Entente/Allies with promises to maintain the Lands of St. Stephen (something impossible after Romania's entry to the war in 1916) because otherwise the idea is never going to gain traction outside the relatively small opposition parties in Hungary.
But let's accept the premise, A-H collapses and the vultures are circling. Russia immediately sends troops into Galicia-Lodomeria (assuming this happens before the October Revolution), German-Austria will join with Germany because trust and faith in the Habsburg's has been broken and they fear the Hungarians wrath or even some kind of Socialist rebellion (if after October Revolution) this will require no extensive military campaign from the Germans, German-Austria will join willingly in this situation. Serbia will sweep into Bosnia and Vojvodina (definitely) and depending on their strength might try for Croatia and Slovenia as well (literally every Hungarian propaganda leaflets about Serbian war aims come to life) and Romania will, as you say, throw the kitchen sink at getting Transylvania.
At this point Germany is, arguably, in a stronger position. It has gained the resources of German-Austria, plus Bohemia as well in all likelihood since the Czech independence movement only really took off in May 1917, with the Manifesto of Czech Writers, when it became clear that the Entente/Allies were considering the dissolution of A-H and only then became a major force after Wilson's 14 Points speech. Either way, Germany is now a renewed powrhouse with more resources and a more compact theatre of war. There will no more sending troops Galicia or Serbia, just head-to-head confrontation on the two major fronts (though they will probably continue support for Bulgaria and the Ottomans). Not only that but Serbia and Romania could well drop out of the war now that they have achieved their goals and Russia will be spending time trying to convince the Poles from rising up in Galicia and indeed, by this time, struggling with its own massive domestic problems. So, once Russia inevitably drops out (almost certain if Kerensky tries to keep the war going, a decision which only helps the Soviets) a Großdeutschland can throw everything it has at France, meaning a successful Ludendorff Offensive or equivalent is entirely possible. Bulgaria and the Ottomans will probably be worse off though since the collapse of A-H means they are cut off from German guns and men and ai both will probably be defeated quicker, leading to German victory, but not a comprehensive one.
Long story short, the premise is pretty unlikely to actually happen, a Hungarian rebellion does them no favours at all and in fact it would make their situation worse but if it did I have a feeling it would actually help Germany in the long run as they gain access to more resources whilst simultaneously reducing the fronts they are fighting on, this is especially the case since they would almost certainly gain German-Austria without bloodshed (indeed the German Military Expedition to Austria means they won't even have to send additional troops in) and most likely gain Bohemia as well (though that may be more challenging to take, but resistance will minor).