I had no idea there was any English-language scholarship on the subject! It seems to be a fairly unknown subject outside of France.

Idk, I think the fact that they refer to it as "la bette féroce" ("the ferocious beast") and not ever as a wolf (unless I'm missing something /not an expert) -- which they would have been familiar with -- kind of makes me think it wasn't wolves. In all honesty, it was probably some dog/wolf mix. Iirc one of the Chastel was a dog breeder, so he likely had a mastiff trained to attack.

(Of course it could be that all of France was infested with werewolves at the time. ^_^)
I can neither confirm nor deny.

Oh yeah, it definitely became famous because of press hype! Newspaper sales had taken a dive after the end of the Seven Years war, so the Beast was a good opportunity.

Maybe that's the real story: an evil journalist werewolf.