Were the homeowners responsible for keeping up their mortgage payments for the 5 years of trials? If so, they should bill the city for the full amount of mortgage paid and see how they like it. If they were paying for city property then the city should have to reimburse them!
I'll bet money that all of these people paid their property taxes during this period! If so, the city by accepting the tax money, obviously agrreed the property was not theirs and don't have any claim. If they refused the tax revenue, then perhaps they would have a leg to stand on, but I doubt these money grubbing weasels ever turned down a dollar for the city coffers.
This might have to go back to court. Maybe they will get a second chance and this wrong can be righted. I won't hold my breath though. 