Yes, the majority of French releases are vinyl rips. There is at least one that has not been released on vinyl, and I'm not sure what is the source. The good news is that a lossless option is now available. I bought some of them and while most are true lossless, "Mata-Hari" was in fact a rip of the MP3 version (so either the store messed up or Cinemusique used MP3 somewhere in the lineage). Some 7" single are only of average quality. Basically only a standard rip of a EX-/VG+ vinyl. Some like "Un Taxi pour Tobrouk" are rather bad and poor digital noise reduction was applied. Some others, however, like "La Ronde" are from a mint vinyl. Finally, for some of them, there are better lossless versions of the vinyl rips that can be bought from the BNP label.
Yes, the majority of French releases are vinyl rips. There is at least one that has not been released on vinyl, and I'm not sure what is the source.
I can tell you what the source for Delerue's OPERA MOUFFE, Duhamel's DIAMETRE and Ohana's LES DENTS DU SINGE is. They all come from a very rare CD which was released by the French SACEM music society only for their members more than 15 years ago with the title "Musiques des Courts Métrages du Cinéma Francais". On this CD there were scores from French short films from the late 50s and early 60s which had never been officially released before. I also have only a CD(-R) copy of this top-rare CD which you could buy almost nowhere. For example, Jarre's LE BEL INDIFFERENT from 1957 can also be found on this CD.
It's not clear why, this late in the game, some label hasn't issued the MGM LP of THE YELLOW ROLLS-ROYCE. There's no doubt that Riz Ortolani is not a big seller, but still. It could be paired nicely with the unreleased MGM LP for MAYA, also by Ortolani.
It is mostly surprising because both are 1st rate soundtracks, certainly in the top 5 of Umiliani (and I usually prefer the beat-sound). However, both are super-easy to find as mint LPs, so maybe it is a factor?
In comparison, Cintura di Castità was previously a very rare LP until it was released by Digitmovies last year, but I find it one of his weakest.