I understand your reasoning, but I also think it could be easily explained why the noble wouldn't have a house. Firstly, all of the origin characters and the PC were abducted and we don't know how long they've been gone. So they could have lost property in that time. Secondly, they could have a reason they don't want to return to their home, I.E. Astarion who is a noble (not going into details for spoiler reasons).
I would like all of the background to get a bit more though. In 5e, each background has a specific ability that are primarily for flavor, which could be cool to see.
