Wittelsbach grandchildren of Sigismund Vasa

[Jan Olbracht]

Um...no. Karl Philipp is a Catholic, which means it's going to require dispensation(s), one to marry a Protestant (if she won't convert) and another to marry a relative within forbidden degrees.
Marie Hedwig is his aunt (canonically speaking) and while the papal offices had no issue dispensing for an uncle-niece marriage, for one between aunt-nephew they were fewer and further between (I know of only three - Philippe III of Burgundy to his second wife, Bonne d'Artois (who had married his uncle); Ferrante II of Naples to his half-aunt, Giovanna of Naples (niece of Fernando the Catholic); and José, Prince of Brasil to his aunt, Maria Benedita of Portugal)). I'm not saying that it won't happen, simply that I would suggest another bride - Liselotte, perhaps?

What about daughters of Edward of Palatinate?

 

[Valena]

OTL Princess of Salm is of age for the match.

 

[krieger]

"Some support" existed in PL even for absolutism and for vivente rege election of Duke of Conde.

I know. It wasn't backed by immense wealth of magnate families, however. I'm not denying the possibility of the reforms, I'm only stating that it would be rather difficult to pass them through Sejm.

 

[Jan Olbracht]

I know. It wasn't backed by immense wealth of magnate families, however. I'm not denying the possibility of the reforms, I'm only stating that it would be rather difficult to pass them through Sejm.

Poniatowski pushed them through Sejm using confederate Sejm (I mean lots of reforms he already made before 3 May), thus omniting liberum veto, would Prażmowski's reforms be accepted (and these reforms would be accepted if not VR and civil war) Sejm would work like the ones from Poniatowski's times 100 years earlier.
And regarding support for absolutism and vivente rege-some of magnates themselves supported it, like Ossoliński, who wanted to make Władysław IV absolute monarch, or Sobieski, who fought on King's side against Lubomirski.

 

[krieger]

Poniatowski pushed them through Sejm using confederate Sejm (I mean lots of reforms he already made before 3 May), thus omniting liberum veto, would Prażmowski's reforms be accepted (and these reforms would be accepted if not VR and civil war) Sejm would work like the ones from Poniatowski's times 100 years earlier.
And regarding support for absolutism and vivente rege-some of magnates themselves supported it, like Ossoliński, who wanted to make Władysław IV absolute monarch, or Sobieski, who fought on King's side against Lubomirski.

Not so much like in Poniatowski's times. On confederate Sejm liberum veto was simply impossible to use. Prażmowski's proposal only limited usage of liberum veto to so-called "constitutional" (for example liberum veto could be still used when the law trying to abolish free election would be voted through Sejm). And work of Sejm from Poniatowski's times wasn't exactly perfect. Sure it was better than in Wettin times but for example during Poniatowski's reign happened an event called Sejm Czaplica, when the anti-Poniatowski fraction of nobility led by bishop Kajetan Sołtyk and bishop Adam Stanisław Krasiński tried to depose Poniatowski. And in Poniatowski's time the great Russian bear had a say in every event happening in PLC. Sigismund IV is much more independent than Poniatowski, but what will he plan during his reign? If PLC is pro-Austrian, the Great Elector might even give Sigismund IV an offer of joint war against Sweden, ruled by baby Charles XI.