I am sure they will. It was somewhat popular on the 4th gen, the Rambox with 6.4 box, so not sure why they wouldn't offer it at some point for the 5th gen. May come late though, I know it will be "late availability" with the shorter box on the 1/2 ton models. The 3/4 and 1 ton models probably won't get the Rambox as an option until end of 2020 or later.
And I doubt it with the air suspension. The Limited has every option, pretty much, and Ram really loves their air suspension system. I could be wrong though, Ram seems to have listened to feedback on the 4th gens quite nicely when designing the 5th gen's features.