Zoro - I'm not sure how much teaching he'd do ... maybe a few comments here and there ... but he would never say no to a sparring partner. I think he more hangs out at the dojo to focus on his own training, which includes anyone interested in taking him on. lol.
Hinata - She's super friendly, so I don't see an issue with them getting along. lol. I mean, Naruto is a scruffy, fighty, nine tail jinchuriki. Sooo, she can't really say anything.
Haru - lol. Haru tends to come off as a little weird, so he's alright if Rin thinks of him as such. His matter of fact comments can come across as rude but he doesn't intentionally try to be ... for the most part.
Riza - I feel like he would remind her of Edward, so she'll probably like him in a "you're funny" sort of way but still kick him in the butt when he needs it.