Lenski ... first let me say I was impressed by some of your daughter's catching mechanics. This looks to have been trained ... and she has learned well.
Second ... what we see here in your daughter's swing goes well beyond that of a change-up. And as with your daughter's catching, what she is doing in her swing looks to have been trained as well ... albeit this time not to her benefit.
Question ... why does your daughter throw left-handed but bat right-handed?
I ask for multiple reasons ... one of which is that your daughter is performing an odd mechanic in her rear shoulder when she swings. Her connective process does not involve proper scap action ... and actually bypasses it. Did your daughter receive training at one point that gave her a goal of having a vertical rear forearm at any point in her swing? Her swing has that appearance.
Firstly, thank you concening my dd's catching mechanics. She was taught by me. I caught back in the day.
Secondly, this happens to her every school year for some reason. When she sees live (slow) HS pitching early in the season, she leans forward and does other odd stuff like she's impatient or something. Eventually is smoothes out.
Thirdly, because she's a weirdo. She throws, eats, and writes left-handed, and does about everything else right handed. It's just how she is. I tried to make her hit lefty but she wouldn't have anything to do with it. She can throw right-handed better than most girls even though she throws left-handed. On her old travel team she had the strongest throw (by far) left handed and the 3rd strongest throw on the team when she threw right handed.
A couple of MLB players off the top of my head that throw left and bat right are retired A's outfielder Ricky Henderson and the Reds Ryan Ludwick. I'm sure there are some more but I know it is very rare.
And fourthly, no. She has always been taught that the top hand should always stay in front of the elbow during the swing.....not that she always listens.