I went through the FOIA process again and was given the most recent revision (Rev 5) of the RFP document
@Paniolo Man requested. It's attached.
I haven't had time to comb through the content, but the changelog near the top is really helpful. The chapter 1 conceptual car arrangement figures are gone, and more clarification was made on accessibility in upper and lower levels. Most of the room types (premium, accessible premium, accessible twin, accessible double) and a lot of amenity details (skylight, first class bar) were also removed. Maybe giving more freedom to the builders will help.