Keeping aside Hulda and the elf from Drunken Huntsmen and Jenassa, I had nothing better to do than see what people did after hours, curious where everyone went and such. I noticed several other Npcs who acted strangely post civil war quest (which I added an issue for elsewhere), though I believe these are always been this way.
Amren is one, very late at night he heads to the Drunken Huntsman for a drink and around 2am heads out, but continues to do laps around the city clockwise until sunrise.
Brenuin the bum also in a similar fashion drinks at the Bannered Mare until about 2am before heading out and wondering a similar path to Amren, slightly altered though. I still haven't discovered where he has ever slept.
Tilma the Haggard in Jorrvaskr is always up and about, before and after the companions quest line has finshed. Waiting results in her jumping from upstairs to downstairs. but always in some kind of idle.
Saadia does sleep it seems, but the second you walk through the door she gets out of her bed and heads downstairs to do her jobs as a waitress. However if you wait out your time in the Bannered Mare she will never go to sleep.
Lastly is Gerda and Fionna in Dragonsreach, the two cleaners. They head downstairs to where their beds are, but both will sit at the designated idle seat areas next to their beds.