They can go into that housing lot and like a free company room. No body's house conflicts with there own. How would a ward be populated? Free company's. If a free company buys that land. That they would be able to build in the open world part of that lot. It would appear in the open world part of that lot. Independent players would still be able to go and click the sign to enter their private instance.

If a player has a spouse he/she can go up the sign and click on a tag example [Spouse: John Henry] to enter the house of their spouse. Players on you friends list would be qualified to enter as well just replaced spouse with friend on the tag. The independent player would be able to lock it so people of the friends list could not enter.

That is just one way to solve the housing problem.