I'm reviving this as it to some extent covers what I am wondering about, although I haven't downloaded anything from any exchange, CC or anywhere, other then from the bin that comes with the game.
I have the boxes at the bottom of stairs, saying they shouldn't be in the game. I haven't checked to see if they are there in live mode, as I have been working on creating my blank "utopia" town in MF.
I placed two different houses, one called Doubleday Lodge, and I don't remember the name of the other one. They are beautiful homes, I did some remodeling, not much, removed a set of steps (one on each side of room, don't need both and could use the space for something else) in one house, but mainly landscaping.
Anyhow, has there been any new information on them, what the boxes are for? If they aren't seen in live mode and doesn't affect the game, then I can just move them out of the way and ignore them.