You mention limited off road use, so perhaps staying away from suspension forks would be a good approach? You could narrow the choices from there.
A used 26" rigid mtb in XXS or 13" or whatever would be great. Toss some slicks on it instead of the heavy and slow knobby tires and she could have a great bike that is more responsive and lighter than a new heavy cheap forked suspension mtb.
Used rigid mtbs, depending on what you get, are typically great deals- cheaper price and WAY better components than something entry level and new. Of course, it means finding something in her size that's used.
Buy rigid frame
Install slicks
Kid has fun
Whatever you decide(new or used, rigid or travel fork)- don't buy a bike for her to grow into in a couple years. That means 2 years of a bike that's too big. Yes, kids outgrow bikes and its a money suck- but there is craigslist to buy used bikes that others have outgrown and sell your old ones.