Hi Don .. as you are finding out French Hornby can be a very different kettle of fish compared to the English variety . This is because on certain lines Hornby Francais had a free hand and were basically autonomous when it came to design and production of local product , although of course they DID make use of various UK components and models , and I suspect espescially just before and after the war did incorporate a number of Hornby UK leftovers?
The roof on your odd man out French Pullman is much the same as the UK Hornby No.1 Pullmans , so I suspect that maybe France got the moulds and tinware when the UK had ceased No1 Pullman production ...
SO although I cant give you a definitive dating on them I would suspect mid 30's to late 40's which ties in with your research and the drop link couplers
News just in ! ( lol )
Binns Road has a green roofed version dated as ... dum dum duuuummm!
1931-36 ... as you will see on that page also ... drop.link and automatic couplers were both in use at that time period ...
http://www.binnsroad.co.uk/rai...r/coaches/index.html
Binns is by no means definative but it does a good job mostly 
I think for a more definitive look at Hornby France you would probably have to defer to Clive Lammings book on it ( which I dont own cos I can never find a reasonably priced copy! )
