Certainly a proper diet coupled with an effective excercise routine is going to be good for her.
I am unsure about the specifics of resistance training on youths (ie your deadlift question). I would think if proper form is followed they shouldn't be bad though.
Quickly looking at her diet I don't think it's probably the worse ever, but it could certainly be better with more protein and more veggies.
I would def open an account on
www.fitday.com (free) and see what her daily intake might be. If you do a search for the Harris benedict formula you can use it to get a ballpark idea of what her caloric needs might be.
Og.