I don't know anything about fastpitch pitching, but should her front knee/foot be more straight here? And is her front arm and torso opening up too early?
Yes and yes. That said, she looks young and strong front side resistance - to include shoulder rotation - requires a degree of core strength that many don't develop until they are a bit older.
Its like an explosive drive....you emphasize it in practice when they are young to develop good habits, but don't expect them to look like Scarborough at 10.
Drive and FSR are two things they will work on constantly and two things that can always be a little better.