Once you nail down the new and improved swing mechanics, get her a better composite bat. The yellow Easton Synge is just ok (used to own one) but the higher end composites are worth the extra money.
As someone who regularly suffers from the terrible affliction known as GAS*, the thought of a new bat has already been rattling around in my head. However, this is pre-season, she still hasn't made up her mind 100% if she's going to focus on softball or cheer, and - as you mentioned - getting her mechanics improved are the priority at the moment.
* Gear Acquisition Syndrome - The un-ending desire for more/better/newer equipment.