How to change the Skybox:

To change the sky, go into console type "fw" followed by one of these codes. Type a "1" at the end to make it permanent.
SoulCairnAmb01 02001407
SoulCairnAurora 02006aec
SoulCairnAmb02 02018dbb
SoulCairnAmb03 02018dbc
SoulCairnAmb04 02018dbd

SoulCairnAmb01_Rain 02014551

Example: fw 02001407 1

How to Make a NPC home your own:

1. Move the NPCs outside the structure in the interior cell if you don't want them and mark them as initially disabled.

2. Change the ownership to Playerhome

3. Unlock the door and change ownership to Playerhome or none

4. You can ignore the quest because it will not progress unless you have a dialogue with Grosta (who is now disabled).

5. Now make any changes to the interior that you want, but don't delete anything just move it like you did with the NPCs and set to initially disabled if you don't want it in the house. The same applies to stuff outside the house as well.