The NCL web conference just ended and we now know more about the Undercover Boss episode.
Kevin Sheehan actually did many other jobs including cleaning cabins and working in the crew laundry issuing uniforms. CBS decided not to use that footage and it was the show's producers who made the call on what segments were used, and NCL didn't know which segments would be used until the show aired.
The cabin on the Epic was "on the periphery" of the crew area and was a single cabin with private bathroom. They have some of these cabins and use them for guest entertainers, although some full-time crew do use them, so technically he was staying in "crew quarters".
The guy who was promoted to Assistant CD...well, he was already scheduled to be promoted but as the ACD on another ship. So the fact is he was promoted but just not transferred.