I'm not too concerned about the buttons, they're fairly wide. But we'll see how it goes. Part of what I'm going to be doing is having a front-closure for the hauberk, so if it comes to it, I'll put a leather backing on the hauberk there.
I hadn't really thought about tie-on mittens, but I'm sure she could do it (and she's usually pretty excited to try new things).
She charged me her normal gambeson price ($350), but I think she said she'd discount it a bit since she ran past her time estimates (it's a month late now).