Actually the term stateroom is not so far off the mark. Although we call them cabins in Canada, US Navy officers do call them staterooms.
HODs in destroyers have single cabins.
Captains and Commodores do not share cabins. They share a common area, but they each have separate sleeping areas. In destroyers they also have their own heads (can't say for CPFs).
MARS officers frequently stand more than one four hour watch in a day. In a one in three rotation, that works out to three watches a day for two days followed by one day with only two watches, then the cycle repeats itself. I'd say that pretty much qualifies as shift work, although I gather MARS officers don't often stand 1 in 3 anymore.