Enjoy the show, Sally!! You have great seats and if you want to go to the stage door, you're in a good spot, as the stairs next to the women's bathroom (which you'll be near) practically land you right on top of the SD.
Someone else mentioned how they warn you that if you sit onstage, you can't leave until intermission. My 9 year old has a bladder of steel and it wouldn't be a concern, but while it's never been an issue for my 7 year old yet, I wanted to make sure we could easily leave if he needed to.
Personally, if it were just adults, I'd choose stage seating, but with my own young kids, front mezz was the way to go. My sister has seen it from rear and front mezz and banquettes, and she prefers front mezz. My husband has been in the banquettes with me in the aisle seats both times and he found the interaction uncomfortable; I, on the other hand, loved it.