2, 14 and 22 for prouvaire if you want? :)
2. Their emotional/moral weak spots
He's not really the one you go for, when you need proper actionable advice. Like sure, he might say something profound or something poetic or something totally outlandish because he's in the mood, or something witty and sharp, but it would not necessarily be good and moral advice that you can use in the moment; maybe someday one of his friends may reflect and think, oh that was very profound but not very useful for my purposes (I really like @pilferingapples's idea that some years later Marius would be recollecting his friends words and the grief train would hit him all of a sudden).
Also there is a very high chance that things he might suggest and or be involved in aren't necessarily legal/moral. He's out on rooftops of abandoned or still in use Gothic buildings or getting into theatre riots or having a Romantic orgy involving several friends complete with punch drinking. He is given to thinking about issues of economics and of women and children so any wrong that way would obviously incense him. I also headcanon that he feels fine about using a violence to overthrow the government. He's not conflicted about that, it's very Romantic and apocalyptic for one thing. Death of the old world and Resurrection of a new world that is socialist and cares about people.
I feel like sometimes he might be affected by a bad review of his poetry and make a bigger deal out of it than it warrants because Romantics are drama llamas and extremely ridiculous. He also has a high capacity for Melancholy and Enjolras associates that with him, but Hugo's Melancholy as used in-text is actually a seekret super power, so maybe not really a weak spot.
14. Ingrained habits/forces of habit
I feel like he sits in ridiculous positions all the time. Probably lounging on the sofa or on the mat or something and has been doing this for a while. Also he reads a book under candlelight late at night which is often in a very precarious position, so far he has managed to not burn his bed.
I headcanon that he's not a very early riser generally, though maybe Bahorel is generally, unless they are deliberately staying up to watch the sunrise, because it is very poetic and he is inspired.
He has a day where he visits friends but it usually leads from doing a favour for one friend to greeting another, to stopping for a drink with a third. He's always going from place to place in a hurry doing little favours here and there, while his pockets are full of manuscripts and he walks around writing on them, as his Muse strikes.
He also loves using different pseudonyms for each and blushes strongly if someone praises his work too much. He loves singing sometimes, possibly not in tune but because it makes him happy or playing the hurdy gurdy, also out of tune.
22. People who’ve influenced them greatly
Other Romantics that would be his contemporaries, possibly also older Romantics. He's also enough of a history nerd, imo, that he would read Medieval poetry and be inspired by the poet or characters, or be inspired by people from history especially revolutionary history that he might have read.
All his named friends. Also Enjolras so much. And Bahorel.
Andre Chenier as a poet, probably, as that is canon. Mythical/semi religious figures definitely.
