I thought they were just going by the book with Gavroche's song at the barricade. I've never seen the unedited version of the musical, but I'm fairly certain Gavroche sings his Little People song in the book when he's collecting gunshot powder. It was just his way of saying "Screw You" to the Guard. Eponine's got a bit of a bigger role in the musical proper. A few more lines of her flirting with Marius and him completely ignoring it (Marius is either the most unbelievably oblivious guy or the biggest dick in all of musical theater) and she delivers the letter to Valjean for him. Then she gets shot climbing back over the barricade and Marius' first reaction is to ask if she delivered his letter. I dunno if the unedited version has anything in it, but I really wish there was just a line or two with Marius telling the Thendardiers their daughter is dead and calling them out on being horrible people. He does hit them in the movie, but it had nothing to do with Eponine As for the students, the only one who gets any sort of characterization (besides Enjolras) is Grantaire, and even that's minimal. He's supposed to be this drunkard who cares nothing about the revolution and its ideals but has this giant mancrush on Enjolras and is willing to follow him anywhere. If you pay really close attention during the musical you can pick up a bit of it, but I never would have noticed if I didn't read the novel. I wish they had've played that up more in the film as I think it would've made his death scene much more powerful.