I think the double bubble roof plays more in the role for extra headroom. I think the backseats were axed because of the short wheel base and weight savings.
Nissan Says GT-R50 By Italdesign May Enter Limited Production At $1 Million A Piece
https://www.carscoops.com/2018/07/nissan-says-gt-r50-italdesign-may-enter-limited-production-1-million-piece/
I was thinking that as well, but going back even the prototype with the crappy wheels and brakes appears to have the same seats.
https://www.supramkv.com/threads/2020-toyota-supra-spied-testing-at-the-nurburgring-4-minute-video.835/
Probably, Medrivfast told us a few weeks ago that his neighbor is able to take the prototypes home. My question is are they able to give people a ride in one? :D
I'll be visiting CA at the end of summer. Hopefully they'll drop the body cladding by then so I can take some nice close ups for you guys if I run across one.