Board size sounds about right for what you're looking to do. You could certainly ride a longer board but if you're looking to do some park and jibs the 56 is a good size. Custom is a pretty popular binding, middle of the road. Moto is a soft-ish boot that will do the trick as well.
Can't speak to the wife's gear, though.
Bottom line is that whatever your shop set you up on is likely 1000% better than any rental gear your going to get, so even if it's not top of the line high-tech new new stuff, you're still going to have a good time on it. Enjoy it!