A word of caution about rocking the front foot. My daughter was called for illegal pitches in an ASA tourney because she was rocking her foot, umpire said if she rocked her front foot she had to start with heel on back edge of rubber, not the front edge. He explained to me after the game that she was pushing off from something other than the rubber and that was illegal. She was starting with heel on front edge and rolling forward which, in reality, was was letting her push off about 6 to 8 inches in front of rubber. After talking to PC, we eliminated the rocking!
I use a plate with a mat and I think it helps pitchers with positioning and feel. More importantly though, her glove side is not helping her with her drive, as it should. Both arms should swing back and then thrust forward simultaneously for balance and an extra amount of counterweight supplied by the arm itself. Finch does this extremely well. I also think she is forward on her release too much and it is more evident in the front view you provided. Her front shoulder is dipped down before her release. Lastly, I believe she is a little early on her lower half in so far as her timing goes. This can be corrected by having her bend a bit more as she begins her stride. I hope I have helped a little.