Welcome to the forums!
I agree with you that the two biggest issues are: she's pulling with her arms and she is racking the bar in her hands.
For the arm pull, watch this: In Depth on the Arm Pull | On the Platform - YouTube
Don't make your girlfriend watch it, you may not have one afterward (it's 30 min long!!).
As in the video, have her start in the jumping position, and have her jump with completely locked arms, making no effort to rack the bar. If done correctly, she should feel the bar slam up into her palms. This will help her to learn the "feel" of a straight arm power clean.
As for the rack position, can she get into a proper front squat rack position, without cleaning the bar? She may have to widen her grip to achieve a proper rack. Make sure she open her hand, letting the bar roll into the fingers onto the anterior delts.
If she can do this, then she has to decide to "jump and catch" by slamming the elbows up. Fixing the arm pull will help with this.
If she can't get into a proper front squat rack position even without the clean, there are stretches in the book and on youtube that will help with this, over time. I assume she's just not letting go of the bar.