If I get the OP's original question correctly, then the answer is simple. The bus you are converting doesn't have a copilot seat so why would there be a law requiring you to install one.
Are you going to leave the door there or just have the big empty space with the highway viewable from the front couch? Enjoy the rebuild as they can be as much fun as the camping and traveling are when you are done.
Denise and Dennis Dalla-Vicenza Co-pilot Mizzie
Gracie a Winnebago 29 RQ + George a Suzuki Toad
. (Co-pilots emeritus Furb, Izzy & Mikkael)