I actually just figured they'd be by their soup cart all the time, didn't figure they'd have a house you could visit because they'd never be there, since they be out selling soup or playing music. There's usually lots of people in video game towns who you meet outside but don't have a corresponding house, as it would be empty, because they're outside. We don't need to make empty houses, unless they're there for the plot or for a hidden treasure.
Speaking of which, we could have one or two empty houses in the slums, maybe one in the rich part of town too (probably that one where the only way in is the ladder on the roof. Or one you can only access via the chimney.). Instead of someone living there, we'd just have a puzzle with a reward like a piece of heart, some rupees, seashells, or rings (if those get accepted).
The apartments, by the way, look pretty good. Maybe different people would have different rugs instead of them all matching.
Also, we might change a couple of the apartments depending on who ends up living there. We have a lot of un-reviewed NPCs (I did a bunch last night), and some of them can go into these ? houses. Also, other people can submit ideas for NPCs to live in these houses. I will review any ideas anyone else puts in there, but I can't exactly give myself feedback on my ideas :p
Hint hint, someone else should review some NPCs so we can have people to fill in Hyrule Town.
So yeah, summary- the empty apartments will probably need to change a little bit depending on accepted NPCs who fill them. Feel free to add you own ideas in the NPC board or the Locations board. And somebody look over my NPCs, lol. Then we can get the question marks filled in with something, and do those locations.