I think about two different solutions for housing, first is make in lands board an "upgrade" price, that is the price of land, discounted by the paid price of actual owned land. If you purchase with "upgrade" price, you buy the new land and at same time your old land is released.

The second, to address the problem of losing house and furnitures, it may be great have a "land ticket" that the FC master can sell on market at the price he wants, and whoever buy it, will take over the house property, switching owning FC.