So we decided to order a rear seat for the green one. When it came in, the mounting brackets were not for ours so yesterday, I spent the day doing some metal fabrication and cutting to mount it up.
I removed the roof and rear roof support bars followed by the rear basket. Once that was gone, the lower brackets came off to be cut down as they had bars extending out to hold the basket and to make room for the rear seat backrest.
I then had to fabricate a bracket and support bar for each side of the rear seat with a piece of thicker sheet metal and some 1.5" flat bar steel. Once I cut and bent the sheet metal and flat bar and did the preassembly, I took it apart and painted the brackets then reassembled it. I got finished in the dark at 9pm last night. The seat flips to create a flat bed for hauling things.