Hey ho,
currently I'm working on the retopo of my character, I looking for unnesecarry polygons and build shapes that follows the folds better to support the normal map on top but doesn't look to flat from the 3/4 view.
The head is a tricky one, because I'm working with a mouth open head for the bake, I have to use a mouth closed blendshape which means I have to prepare later a retopo head with the same vertex Ids and topoligy to be able to project the pose.
Anyway, here a a few screen grabs from the retopo version
During the retopo of every single piece I made test bakes to see if the current shapes works without baking and normal map issues.
Here are images of my latest test head bake.