As I know... Don't quote me, because I'm probably wrong.
But the only way I know of to animate a wow model is in mdlvis.
Which I have no idea how to convert it back to m2 with the tools available.
Geosets just make the mdx to m2 freeze up.
Without a lot of Hex editing which I don't know how to do, I think you would need a tool to do this.
Which I don't know if it exists.
Again I'm not extremely experienced with making race models. hell I'm very under experienced because I can't convert one haha.
If you want to do something like make new animations you may have to confront someone in the community who is good at conversion aswell as the animation aspect.