So many mixed cases here!
The quad=plex/Duplex thing is a HUGE waste. I know they are trying to leverage the people out, but not knoing what the actual SF of the place is, it is awfully hard to determine whether or not they are seriously thinking of doing this.
I think the moving in of family is a little excessive.
As for the 8 apartments with the 4 free, the landlord is not doing things right. The only person he does not have getting their own apartment is his dog.
The SoHo loft renter should be entitled to damages from doing certain things, but it looks like she was a deliberate rent-squatter that was abusing the system. If she had enough to BUY TWO RESIDENCES as well as commercial real estate in NH, and had the nerve to get a drivers licence in NH (to lower her insurance rates, no doubt) she should be kicked out.
As with any system, it is abused on both sides by all those that can and dont have the concience to treat things fairly.