I'm not sure which Kinnect unit you wish to use. If it is the original one then forget it. Facial motion isn't captured. The unit does work for full body capture. I've worked with the original for a couple of years now. I do not have the new Kinnect on Xbox 1 so I cannot speak for that unit.

I do not know of a Mac version of any capture software using the Kinnect. The API and Dev Kits are out there so someone may make a port for Mac but as Kinnect works on a Win machine I wouldn't count on it.

I'll ask my Mac programer buddy if he has heard anything about this but I wouldn't hold my breath.

 As an after thought could you use Poser's Talk Designer to get the animation you need if it is only facial?