1) are you using the stand alone versions of PCMS Builder and Site Sculptor? or using Design Extender?
In the stand alone versions, the CMS included in Site Sculptor is a limikted version, you would be better of creating the site without CMS, then adding CMS Builder after the site is created.
In Design Extender, the CMS versions are identical.
2) No, CMS Builder does not offer a way to assign sections of the cms to certain users.