This is a back-flip change-up, and the first videos are of a curve-ball.
Thankz....a CU that dropped close to 16", had it been slower....That might explain also the jump at the end....her motion is in what I'll call Hyper Fakeout....So she is correct to turn both feet sideways....and to cause Resistance all with the lower half to slow the ball down, while giving the fast pitch intensity look.... :{)