Austria-Hungary has a population larger than France (at around 54 million), and historically mobilized somewhat over 50 divisions at the outbreak of the war. This was a much smaller portion of its total population than any other power in the war, especially after Russia (unwisely) tried to draft as many soldiers as possible in response to the defeats in East Prussia in 1914. The predicted collapse of Austria-Hungary on mobilization not only failed to materialize, but civilian morale was by most accounts enthusiastic. Not only did Bosnia not revolt, but the Croats and Bosnian Muslims rallied against the Serbs; and the South Slavic contingent of the Empire was extremely notable in its role defending against Italy later on. The Hungarians and Germans of course were also reliable almost until the very end when defeat was not just inevitable but immanent, and for the most part the Italians, Romanians, Slovaks, and Ukranians in the Empire were reliable enough. The biggest problems were among the Czechs, due to the collapse of a pair of Czech brigades in suspicious circumstances and above-average rates of desertion and the commitment of the Czech political establishment to a pro-Russian line that led to their large-scale imprisonment soon after the start of the war. Well and the Orthodox Ruthenians being even more pro-Russian but they were a small enough group.
In any case Austria-Hungary held together surprisingly well through 1917, when several fatal circumstances began to catch up to it. Wilson's 14 Points seemed to commit the Entente to breaking apart the Empire as a precondition of peace; the strategic balance was decisively swung against the Central Powers despite victory over Russia by the entry of the US into the war; and the Entente blockade was biting into the availability of food supplies. By late 1918 the divisions on the Italian front were literally starving in their trenches, the Americans were beginning to arrive in force to France, Ludendorff's decisive offensive had failed, Bulgaria and the Ottomans were all but out of the war, and the political leadership in the non-German provinces were looking to protect their own interests post-war by turning against the Empire. Even after the literal desertion of Hungarian units from the Italian front at the instigation of the Hungarian Diet, and the Italians rather treacherously misinforming the Austrian command about the time the Armistice of Villafranca was supposed to start so as to take as many prisoners as possible in a surprise attack against no opposition, von Boerevic was still able to put together a coherent army in Tyrol that was demobilized at the end of the war.
Anyway, worried about a defeat spiral? Then don't get started on a spiral of defeat. Victory will reinforce home morale and promote belif in the continued strength of the Empire. Failure (and the blockade, and Germany pissing off America) is the ultimate cause of the Empire's failure.
Speaking of which, is there any point to diplomacy trying to influence neutrals or promote revolt or what-not? The Polish Legion of Pilsudski originated in the Austro-Hungarian Empire and was employed in the invasion of Russian Poland in 1914 to promote a revolt. The Central Powers had pledged early on to re-establish a Polish state and following through in a more decisive manner might be worth a fair bit of goodwill. Also of course getting Bulgaria into the war does very bad things to Serbia's strategic position and would afterward allow a direct connection to the Ottoman Empire so that's something to work on.