make her skip a little off of each foot would bring this to life more

I think the problem with the feet is that they're completely static, and the motion is entirely in the ankles. The main reason to standing on one's toes like that in boxing is because that allows a lot of motion, and that motion comes from the feet. The feet change orientation relative to the floor, and that makes the body bounce. Try it yourself - you'll find that your ankles barely move, all the motion is in the feet and hips. The hip motion is also missing from this animation.