Just to follow up and answer the "How is the couch anchored" question:
The white arrow points to a strip of wood covered with a black mesh (looks like carbon composite or something). From what I can tell they first screw these strips of wood to the floor and then bolt the couch to it.
I could see screws in the top of the wood going into the floor and then bolts captured between the floor and the wood going into the frame of the couch. Shop4Seats must provide a template or something so that you get these frame pieces mounted to the floor in the proper position so the couch just sits on top.