1. Is it just me, or does not!Fraunces look older than both Fredersdorfs? And I know paintings aren't photographs, and artists differed in how much they prettified, but if these two were painted at or shortly after Rheinsberg days, he should look younger.
Exactly. The only other Fredersdorf painting I know (the non-Pesne one) shows him older and also thinner, more haggard, so while the Pesne Frederdof might develop into either of those guys, it doesn't make sense for Not!Fraunce to supposedly be earlier than the other two, that man is certainly older than the guy from the Zernikow painting.
Now Pesne's male depictions do resemble each other (unless he's painting FW!), as you note with the Fritz portrait, and wig and formal wear enhance that idea. Since Pesne was THE fashionable court painter for two and a half generations, I bet a lot of painters were imitating him, especially his younger Fritz portraits, and who ever is depicted in the New Jersey portrait could easily have been depicted by someone who wanted to see himself stylized a la Fritz-as-depicted-by-Pesne. So I'm going with "not Fredersdorf", but you should contact this Dr. Kuhle anyway.
Re: Paintings of Fredersdorf?
Exactly. The only other Fredersdorf painting I know (the non-Pesne one) shows him older and also thinner, more haggard, so while the Pesne Frederdof might develop into either of those guys, it doesn't make sense for Not!Fraunce to supposedly be earlier than the other two, that man is certainly older than the guy from the Zernikow painting.
Now Pesne's male depictions do resemble each other (unless he's painting FW!), as you note with the Fritz portrait, and wig and formal wear enhance that idea. Since Pesne was THE fashionable court painter for two and a half generations, I bet a lot of painters were imitating him, especially his younger Fritz portraits, and who ever is depicted in the New Jersey portrait could easily have been depicted by someone who wanted to see himself stylized a la Fritz-as-depicted-by-Pesne. So I'm going with "not Fredersdorf", but you should contact this Dr. Kuhle anyway.