Thank you so much for this thread. I don't know how I missed it. It is like a curious puzzle. I have wondered about Caroline's friends before. It is fascinating to see her and her buddies when they were the young swells about town.
Marie Niarchos apparently married "playboy" Alix Chevassu, right? I guess he was a friend of Junot, supposedly. Are they still married?
Isabelle Poniatowski, says French Wikipedia on her father's article, married Bertrand de Maigret in 1967.
I looked up Sabine Poniatowski-Perse. Apparently she is a "privatization expert" for the German Finance Ministry. French Wiki does not have her as a sister of Isabelle, but maybe they are cousins, who knows?