the skipping animation you see when you're previewing a skin is that walking animation, minus the jumping, but i dont know how to find it. you might be able to re create it yourself or get it from PMC itself somehow, or maybe email one of the workers for mojang like jeb. my idea would be to look for the animation somewhere in the latest minecraft version files, it might be some json file or may even be inaccessible, or part of the game itself that you cant change. hope this helped.