To be honest, in the musical there's not a whole lot of individuality among any of the boys, save for Enjolras and Grantaire. It's not even really that noticeable when a production will separate or combine the parts to fit their cast size better. Not unless you're very familiar with the usual distribution of things. There's probably much more about them in the book he never decided to read.

"I would love to hear about them, if you're up for it."