I feel like the leaping and what I call the Pac-Man finish are related to the push off.Havent read the other replies yet. But I can tell you the leaping is usually fixed by staying closed and keeping your back knee pointed to the catcher initially and at the end of the pitch. My Dd had a leaping issue, and still does occasionally. What worked was footwork drills where I would have her keep doing her strides with the intent of not turning her back foot before the stride and keeping her back knee pointed to the catcher.
Also, I'm not sure if you were already aware, but your DD has a leaning forward issue, which if corrected, could give her more velocity and control. That issue could be worked on by having her get taller at release. However, I suggest you work on on thing at a time. Good luck to you.