Lead with a flexed elbow and the palm facing up going into release. The upper arm should pull the lower arm, which is more-or-less going along for the ride. Think whip. There is no wrist or finger snap in softball.
I also notice the glove arm going way off coarse, rather than staying straight in front of her. She does have a nice whip though. Looks like a good start.
She looks great. Could probably get more open when at the 12 o'clock position and it looks like she may be swimming with her glove hand a bit. But overall looks great!!
Swimming with her glove hand is one of the primary things not allowing her to open more. Her swimming arm pulls the shoulders which pull her hips. Should be reversed, the hips provide core torque for the shoulder. Hips drive shoulder, shoulder drives arm, arm drives forearm, forearm rotation/whip drives wrist rotation/whip. So I've been told...