There would have to be concessions to the nationalities, but most people couldn't imagine a breakup of the monarchy right up to autumn 18, and the army remained loyal until the final collapse. But I'd argue that the second Russian revolution sealed the fate of the Empire. The Empire had been a 'historical necessity', a needed counterweight to both Russia and Prussia/Germany since the congress of Vienna. Until Lenin's revolution, the British in particular could have been depended on to preserve Austria-Hungary to prevent the inevitable domination of the resulting gaggle of small, impoverished, powerless statelets by either Germany or Russia, and if Britain had to screw over their allies at the peace table to do that, so be it, doing that isn't kind of the Anglo-saxon leitmotif for nothing.
The revolution changed all that. Communist Russia would have absolutely no appeal to the elites of eastern Europe, panslavistic or not, and I don't think British class arrogance could even envision popular sentiment (pro-Soviet or otherwise) influencing the course the elites (and governments) would take, instead of the other way around. So Russia would be isolated, the Great Game won at last, and together with the French they could keep Germany down, militarily impotent and economically weak. Even better, the breakup would sever the web of economic interdependencies in the former Empire, end its fast economic growth and industrialisation before the war, and create new markets for Anglo-French wares and sources for raw materials. National self-determination was just a propaganda slogan, aimed especially at the Ottoman and Habsburg Empires, not an ideology any of the movers and shakers in the Entente believed in (especially not concerning their own subjects).
Of course, now, with hindsight, we know they miscalculated badly, and the area in question went on to become first German, then Soviet puppets.