The negotiating strategy is you limit yourself to the 'balanced' share in the south *in return* for a big chunk of Belorussia.
So Belorussia remains Polish? Here is a problem as defined by S. M. Soloviev: by agreeing (in OTL) on a balanced share Catherine lost because she got for
fighting and great expenses an equal share with the countries which got their shares for nothing.
An initial very reasonable peace offer of everything east of the Prut with Wallachia/Moldavia as vassals. Then when Austria freaks out,
If the Ottomans signed a peace then Austrian hysteria on
that issue is irrelevant: it is not their territory and they don’t have power to interfere militarily.
agree with Frederick it would be really sweet to have Royal Prussia...Then graciously offer to let Ottomans have everything back east of the Dnieper and an equitable (unlike OTL!) partition of Poland. Then clarify if Austria *really* wants to go mano-o-mano when Russia controls everything Russia would have interest in annexing anyway while Frederick is drooling over Royal Prussia and risk being the only great power of the three to get nothing... Trick is to figure out how to have Austria be the one out of position getting a rawish deal rather than Russia like OTL but I have faith in you...
Sounds quite “Kaunitzuan” (intended as a compliment 😉) but offering Ottomans “everything back east of the Dnieper” is a non-starter: relieving the suffering Orthodox Christians from a cruel Polish oppression was of course a noble goal but on a list of the priorities getting the Khanate (even as an independent state) was much more important. In OTL this was the main stumbling point in negotiations with the Ottomans. Another problem is status of Moldavia/Walachia. The Ottomans could (and eventually did) agree upon the Russian approval of the rulers but never upon making them Russian vassals. Perhaps you meant “east of the
Danube” and west of the Pruth? Which gives the principalities back to the OE.
Royal Prussia for Frederick was not really a controversial except for the status of Danzig region so he is already on board with Russia. He does not really care about anything else but getting his share is subject to settling things with the PLC and for that he needs Russia. Well, he also does not want excessively big Austrian share and for this he also needs Russia.
On the last issue there is actually no need to invent too much because initially, Austrians were blamed most. Russia had an excuse of being de facto at war with the PLC over it reneging on the officially accepted conditions. Prussia was an enemy almost by definition and also had a dissident clause so its behavior was expected. But Austria had been posing as a friend and did not have any issues with the PLC whatsoever so its behavior was inexcusable.