No, they are being morphed along with the rest of the image. You’ll need several poses, front on, 1/4 view, 1/2 view 3/4 view, side view to begin with. But they are reuseable.
The real issue is how many pieces you have to break it down to. For instance closing eyes can be a pretty complex affair. I don’t know if you can really track that. If not, you’ll have to create some nulls and sliders to do so.
However you approach it, it is a LOT of work to do something like this.
If something less ambitious is workable, you could check out some toon shader plug-ins. They do the work mostly automatically, but obviously they don’t look as good.