The biggest thing we've always focused on was coiling into the backside and maintaining that coil until she was ready to unload by resisting with her hands against it i.e. turning the barrel with the hands. IMO the hands control the barrel and the upper half. It makes it less complicated for them instead of focusing on EVERY single aspect of the swing and turning them into robots.
This is really excellent, and you can see it in Brooke's swing.
Lhowser, my two cents only, but focusing on this idea and working with your DD on barrel turn and snap would get her out of her shoulders and clean up her upper half and her entire swing.
You/she are at an interesting point. She is very athletic and you both have a lot of knowledge AND an open mind. Can you change a deeply-embedded pattern at this point in her development? Can she figure it out on a tee AND when under pressure of college pitching without reverting?
I wish you both the best of luck and a ton of fun on your journey I for one would welcome the chance to follow her continued development here at DFP -- it takes guts for both of you to put yourself out here like this.