In the plyg town I lived in, most had separate houses. The main family had a U-shaped compound, with the wives living in apartments in the arms of the U (there were up to 20). The patriarch had his apartment at the bottom of the U, along with the large meeting room and HUGE laundry room. After the patriarch passed away, several wives stayed in the apartments but others bought their own homes.
When they were all starting out and were dirt poor, the families lived in one or two trailers next to each other. Then they went to the arrangements above. Each wife raised her own kids, but occasionally a wife would take all the kids to do something special. The kids did not call the other wives Mom or even consider them a mom. They were their dad's other wives.