I haven't tried this, but I've always wondered it.

In Morrowind, you can kill anyone in any house and take it for your own. Can you do that in this and Oblivion? Or are you forced to live in the homes you buy?

And would your stuff disappear in the chests and drawers and barrels in the house you take?

No. Most houses' chests are marked as owned by the NPC. If you put your stuff in them, odds are they'll disappear. Same goes with beds; they're marked as owned.

I know in Oblivion you could live in the boat in the Waterfront and put your stuff safely in the locked chest. and you can do this in certain houses in Skyrim. you can look for houses you can do this in on the UESP Wiki http://www.uesp.net/