Can't sleep in owned house
Solution 1:
This is a fairly late answer, so I hope your problem is fixed already.
Are you using the Unofficial Dragonborn patch?
If not, please install it and try the pre-finish save again. The patch fixes a lot of developer bugs that Bethesda haven't got around to fixing. In this case it appears that the quest completion script fails to remove any previous trespassing effects and set full ownership. I'm fairly sure I've been able to sleep there when I last played that part of the game.