Argh! Your posts are so awesome and dense that I'm having trouble keeping up with any response - I still want to go back and go over Grantaire's Free Pass re modern fanon (agreeing with you that his behaviour is entirely in keeping with attitudes to women, but grumbling a bit about certain fanonical traits relative to this), and then you go and throw all this fun stuff at us! I don't know where to start!
Re: Isabella's Chemise...I've always heard of this in relation to the legendary beginnings of the colour "Isabella" and Isabella of Castile, and I suspect this is what Grantaire has in mind:http://en.wikipedia.org/wiki/Isabelline_(colour
The connection with Isabella of Austria / The Seige of Ostend was a new one on me.
The Gros stuff is fascinating and, I think, one of the most underutlilised aspects of Grantaire's background, although Abelarda is now working with it in a story that has a fascinating premise. Delaroche I tend to think of as "That Execution Guy" due to his penchant for painting executions.
I never picked up on the tennis thing! Probably because I would have glazed past that when reading in my sketchy French (although these are some of the few scenes I can read resonably fluently due to familiarity with translations) and just accepted the English translation. English translations seem to have a huge problem with Savate and Bâton français and just go with "singlesticks", a concept which the English understood (and tennis, which as you say is just a WTF?). You can see how closely they're related - I tend to break them losely into Fighting with Feet and Fighting with Sticks just to keep them apart in my head, but there's a lot of overlap. I noticed that some English translations forgo the later mention of Enjolras using his carbine in the "Covered Rose" move, or call it a singlestick move, but I'm guessing it's Bâton...and useful as a point of convergance for Enjolras and Grantaire if you want to give them some common ground, as it suggests Enjolras was familiar with this method of combat as well (and given how ferociously and effectively he fights as the barricades fall, I'd say he has some serious combat skillz).
I'm kinda going to give Augustin Robespierre a pass with his attempted "I'm outta here" given that there are pretty good odds his brother had just shot himself in the jaw as a failed suicide attempt. No point in standing by your sacrifice if the one you did it for is trying to bail out himself!