I've been wondering if the fact that he doesn't show up in the "heir" column of Ariane's death record means that he's dead for sure, or if he would have been omitted there either way because he wasn't the oldest. No idea. I guess there is the possibility that he died in 1764/65

Yeah, I've wondered that too. It's possible he entered foreign service and ended up far away, maybe in the colonies somewhere, but it's entirely likely he died circa 1764/65. I've tried searching his name and those years in hopes of finding a death year, but no joy. We're getting into really obscure territory with him, though

although I'm still a bit skeptical re: female inheritance.

Could happen, though; didn't Fredersdorf specify female inheritance in his will?

(The book also briefly mentions Peter and has a chapter on Friedrich Ernst

I see it's University of California, which means my friend the Royal Patron should have access, but since he can't download, only screenshot, and doesn't know even as much German I do, asking him to screenshot an entire chapter would be a bit much.

I managed to read the entire Peter part on page 157, though, due to cunning use of snippet view, and I don't see anything about his burial place, no.

But Jennelt, that's interesting! I definitely ran across that when looking up Knyphausen burial places per selenak's suggestions. There's a well-preserved vault in the church, but my German listening comprehension isn't quite up to the tour. (I also concluded, once I realized where it was located, that it was unlikely Peter, dying in Berlin during wartime, would be shipped all the way out to East Frisia to be buried with his wife's family, so I didn't put a whole lot of effort into following that lead.) But if Carl Ernst Reinhard was lord of the manor, he just *might* have been buried there.