The carousel and peter pan are the same thing I believe…and the plank is close to what you’ve described but I’ve only seen it with one hand (usually below the dancer.) When I learned the plank I just learned it from a basic climb but she will have to be able to tilt her body back and be able to let go with at least one hand. Once she learns the crucifix the cross knee release isn’t terribly hard to learn after that, this was actually one of the first moves I learned but you do need to trust yourself that you can hold on with your legs. I saw your profile pics and you are fab so I’m sure she will learn a lot from having such a great teacher!