I thought they got rid of the smoking rooms in Japan. Maybe not... There ARE conductor rooms which Amtrak needs to figure out how to use instead of manspreading in the Cafe. The Cafe carts is a good idea to keep, and vending machines. I would also expect them to go 2x2 seating rather than keep the 2x2. The phone booths can probably be reimagined, too.My guess is that there may be some tweaks needed (e.g. door width for US wheelchair standards). The "derivative" comment could also leave flexibility to adjust some elements of the seating plans (e.g. having a "full" Green car/Business Class car or moving said car to one end of the train), slip in a catering cart station, dispense with the smoking room, or otherwise adjust capacity. Ditching the smoking room is the most likely change, probably followed by a slight overall reduction in capacity and having a full Green/Business car at one end of the train rather than half a car in the middle.
No current diners on any of the shinkansen as far as I know. Don't think they will be needed for less than 3 hours as long as ample onboard snacks are available.