I doubt Nas will drop last. Can't see him sitting on a finished album (assuming it's finished or nearly so) for the next 7 months.
With that said, Reddit dude had said Slick tomorrow (obviously not the case anymore) and Rae in mid May. So it would seem Rae is up first.
Reddit dude Exact Contribution54 is the real deal plug. Announced the Legend Has It series name, full lineup and the confirmed titles for Rae and Ghost albums weeks back. If they had Rick up first with a title and an April 18 release date, seem like his album ready or very close. Could still be first up and just got pushed back a week or two.
I doubt there's gonna be a big rollout for every album. Maybe drop a video a day or two before the album and do the biggest promo run that first week. I do hope they got physicals ready to go or at least don't take six months to ship though.