Challenge - Saxon-Polish Empire

With a PoD of 1696 (the death of Jan Sobieski), could Saxony have formed a common border with Poland and created an empire similar to Austria's rule over Hungary? To put it in the form of a challenge - by the 19th century the King of Saxony must also be King of Poland and controls Warsaw at a minimum. Bonus points if Prussia is conquered.
 
1) Augustus II is less ambitious. He is just happy with being King and do not even try to reform anything in PLC, which would be only waste of time and resources.
2) Augustus II have different son (say, that OTL Augustus III died as child, Eberhardine also dies, Augustus remarries and have son born around 1715). That son treats PLC just like father (is elected to the throne, because France tries to impose her own candidate, so Austria and Russia support Augustus as lesser evil), but in Saxony he behaves like Frederick the Great. Augustus III is skilled commander, reforms Saxon army to Prussian standard. During alternate 7YW Saxon performance is much better, while for Prussia it is disaster (Kunersdorf ends with Fritz killed?). Saxony gets part of Silesia in peace treaty.
3) Augustus III lives to old age and dies aged 91 in 1806, during Napoleonic Wars. PLC and Saxony are occupied by Napoleon, but after fall of French Empire House of Wettin is restored to the Saxon and Polish thrones in alternate Congress of Vienna as rightful rulers (after over 100 years on the Polish throne Wettins would be seen as such).
 
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