This sounds similar to what I’m doing with my DD. I’m curious what the “follow through path for her trailing foot.” Should be? I’ve seen so much variation and I’m not sure what the best path would be?Absolutely.
Sure, that means just simplifying the drive motion to a point where you're focusing primarily on the lower half mechanics and sequencing. So, from push off the rubber into the frontside plant and what that weight shift will provide for the trailing backside (or previous push foot). You may choose to introduce a simplified/simulated motion (slingshot) if it helps to feel the changes in posture. She's not interested in actually releasing a ball, but just to place her mind within the process in order to feel the mechanical changes that she's working on. A simplified dry run.
To get her started, use a new "template". Use rubberized tape if your inside or spray paint if your outside. Identify targets to include pitching rubber, a linear pitching lane, plant position and follow-through path for her trailing foot. Obviously, video will allow her to see how she is performing compared to target examples.