Admin view/edit content as user
I think  you are looking for this module Masquerade. 


  The Masquerade module allows site administrators (or anyone with enough permissions) to switch users and surf the site as that user (no password required). That person can switch back to their own user account at any time.


There is a module called Role Toggle to handle role toggle.


  This module gives you a page and a block to toggle (switch on and off) any role.