Best change for Austria to take Bavaria peacefully is Bavaria is split between Austria and Saxony (say 2/3rds to 1/3rds). the Elector was the brother in law of one of the Palatinate heirs, plus he didn't want Austria any stronger than it was despite being allies in 7 Years War. However, getting 1/3 of Bavaria would be an adequate compensation for allowing this, especially if his Palatinate relatives are ok with it.
A map of this would be interesting to see.
Or, if Frederick II's relationship with Britain has soured (as it did but not likely this much), he would be allowed to take Hanover. This is a major stretch though.
Even more interesting, creates a Germany that is largely divided amongst Prussian, Saxon and Austrian horizontally-aligned "stripes".
If there ever was a time (before the Napoleonic era) for Prussia to grab Hanover, the American Revolutionary war timeframe was it. It's not like Prussia had any colonial territory or navy to lose at the time.
An assault on Hanover like this would have an interesting effect on the political dynamic in Britain.
The British parliament never liked having Hanover and would have seen the King devoting excessive resources to holding Hanover as monarchical over-reach.
On the other hand, an attack on Hanover could give a strong incentive for an early end to the unpopular war against the Americans. That war had strong critics in parliament, and fighting for Hanover could have been a politically "good war" giving parliament, and importantly the king, a reasonable excuse to cut losses in America. The problem would be winning on land against the Prussians. I mean the British, if extracted from America could send some troops and subsidize Hesse and Hessians (and Austrians) to fight for Hanover, but the Prussians alone, even before we get into other anti-British coalition members (France, and later Netherlands) would be pretty overpowering on land.
Still, if there had been a grab of Hanover at this time, people might well be saying that American independence was won on the fields of Hanover as much as America, and even more places in America might have names like "Hanover Township" (where I grew up) or "King of Prussia", "Frederick", "Brandenburg" and "Berlin".
Viriato:
France was to receive Namur and Luxemburg, the rest of the Austrian Netherlands was to become a Kingdom of Burgundy for the Wittelsbachs. Austria was to annex Bavaria, at least this was the plan backed by Austria and Russia.
A-ha, it would be interesting to see a map of that too. And Russia backed such a plan----I had no idea. Russia must have only given a soft endorsement, because they did not intervene in the potato war. OK, so I see that the Austrians were offering the French something. But in no way was this going to secure them a war-winning intervention in Bavaria.
One version of the Bavarian-southern Netherlands swap I had heard was that Austria was not to gain all of what we think of as Bavaria in southeast Germany, rather just the southern half, with the northern part, just west of Bohemia, remaining Wittelsbach.