Some of the things I'm seeing based on the one swing example...Her front side never gets solid/firm, and she's pushing with her torso over the front leg instead of shifting against the inside of the front leg. The rear hip joint is remaining flexed throughout the swing instead of extending as the torso gets pulled backwards over rear hip socket by the muscles in the back. In short, her swing is an upper-body-powered push, which is not ideal for power or quickness.
Hitters with this type of swing movement tend to have a downward barrel path through contact, creating a lot of ground balls or pop ups.
EDIT: I would put my focus on helping her understand how hip extension and pulling with the back are involved in the swing. My DD will occasionally drift into a pattern of pushing forward with her torso a little bit. When that happens, I remind her about using her back to stay over the rear hip.
Something about the front foot / leg. Notice the pile of dust kicked up. She "lands" open (front foot pointing towards first, but it really seems like a pick it up / put it down kind of movement, vs a stride toward the pitcher.