Hi James
Alot of questions here and many of them not easy to answer without seeing the problems directly.
Firstly - the too high/too low issue. The sights are adjustable and are not set for any given target or person. The idea of aiming off or low is so that the sights themselves dont cover the target when taking the shot. There is nothing to stop you setting the sights so that you are aiming straight at it.
I always set up my sights by taking a shot in the reverse side of a card or white paper. Then I aim for the hole that the last shot just made so that I can see how it is grouping.
Getting the grouping correct is more important than the hitting the target when setting up the sights. Once the grouping is fine and you know your aim point you can then put up a target.
If I was you I would try and get her to shoot using the index finger for pulling the trigger, otherwise she will always get the problem of a grip not fitting properly.
Cheers
Tony