1) go to modify->subD2poly->option box. under tesselation method you've gotta hit "vertices". this gives you the original mesh without added faces and such.

2)4sided is always better. you have to have 4sidedPs when smoothing otherwise you will get artifacts. some rendered problems can be solved overlooking the geometry and, if existing, getting rid of 5+sidedPs.

with the head. if you need to merge the meshes you should go with even faceNumbers.

if nobody will see the "seam" you don't have to merge them.