The only way I can see Genoa being wholly annexed is if the Genoese Revolution still happens but is subsequently crushed, most likely because the French either cannot or will not assist the revolutionaries. Revolutionary Genoa was a shambles; the Serene Government vainly tried to
stop the uprising and was forced to admit to the Austrians that they had lost control of both the people and the army. Many of the soldiers (ostensibly still bound by the armistice) disobeyed their officers and joined the uprising. If the Austrians had successfully fought their way back into the city, it probably would have been brutally sacked, and the response of the empress would have been something along the lines of "good job, those jerks had it coming." With the old oligarchic government thoroughly discredited and the new revolutionary government presumably hanging from the scaffold, the Austrians would have little alternative but to assert direct military control over Liguria (or at least all of Liguria not already occupied by the Sardinians). Guerrilla warfare may continue, but at this point the state has collapsed, and there will be a strong temptation in Vienna to simply declare the Republic a corpse and announce that annexation is the only alternative to anarchy.
In some ways this might be helpful to finding peace, as it gives Vienna some territory and provides new opportunities for negotiation ("Okay Austria, we'll recognize your annexation of central and eastern Liguria if you cede Parma to Don Felipe"). King Louis considered himself a man of honor and insisted upon the preservation of Genoese territory, but in the face of utter state collapse he might relent on the matter. But it may not be great for Corsican independence, because while the nationals would undoubtedly enjoy the
schadenfreude of watching Genoa be crushed beneath the imperial boot, notional Genoese sovereignty also protects Corsica from just getting snatched up by a greater power. If Genoa collapses, Corsica is suddenly up for grabs and probably gets claimed by the Austrians.
It's certainly an interesting idea and I haven't yet decided whether a Genoese Revolution will happen ITTL, although with Schulenburg presiding over Genoa instead of the cruel and pompous Botta Adorno the chances of the same sort of furious uprising are probably reduced.
Have there been any butterflies outside the European theatre? Specifically India and the Americas?
Not as yet, although I’ve been thinking about whether I still want Madras to fall to the British (as it did in September 1746 IOTL). The French victory was only made possible by the inconclusive Battle of Negapatam off the Coromandel coast which caused the British to abandon the coast and leave Madras vulnerable, and this naval battle was in turn only possible because of reinforcements sent from France; it’s possible the French ITTL don't send the same support to India as a consequence of their losses at Dungeness in early 1744. Even a minor change in weather or illness could affect the outcome, in particular if Commodore Curtis Barnett (who was actually
at Dungeness, but by 1746 was in command of a squadron in the Bay of Bengal) avoids his OTL sudden death from disease in May 1746. Barnett is pretty much universally regarded as a more energetic and effective commander than Peyton, the man who replaced him, and might well have commanded more effectively at Negapatam, where the British had better guns and better crews but nevertheless failed to do anything significant.
A British retention of Madras would seriously impact the peace talks in their favor. IOTL Madras was traded back to the British in exchange for the return of Louisbourg and Cape Breton Island to France. Not needing to recover Madras significantly strengthens the British negotiating hand and allows them to insist on other concessions for Louisbourg, or perhaps even to
keep Louisbourg, which would seriously harm France’s position in the Americas.
well know we need to find a beat for our Corsican troops to march to in the Prussian style.
True - while
Diu vi salvi Regina is a nice song, you can't really march to it.