Really, what is a "typical girl?" Sorry for this tangent, but to me, a "girl" is 12 years old. I'm 52 and have had it drummed into my head since the 1970s that it is insulting to call a grown woman a girl, so I just can't abide by that phrase.
Anyway, I am not your typical woman, and I wouldn't think of a dinner hosted by a bf's wife at her home as a first date, but I think a slightly dressier version of business casual would work for dinner there. Nice slacks and a pretty blouse, with a little bling should do it. I would say not to wear anything that is uncomfortable or that you have to fidget with, if being there for dinner will make you nervous enough.
And I wouldn't wear ridiculously high heels if I were you, either, but that's me. Those kinds of "fuck me" shoes were originally made for lying down, not walking around, and I think women look like jackasses wearing them in the street. That's why I call them "Stupid Shoes." But I digress again.
As for your job interview, there are lots of resources on the internet for what to wear. Google is your friend.