I recall reading an interview with Elliot Scheiner at some point in the past where he said he auditioned the 5.1 mix for Van at a studio in London and that he was happy with it, so I think it's safe to say he's definitely heard it.
Around the time the DVD-A was scheduled to be released, or just in the years after, Van was shopping his back catalog (he owns everything except for the first three records, Astral Weeks, Moondance and His Band and the Street Choir) around for reissue. Up until that point, they'd been on Polydor but he was supposedly unhappy with the sales of the reissue campaign they'd done and he cancelled it before the final batch of remasters came out.
It wasn't until after the announcement that his back catalog went to Sony that we saw the BluRay release of Moondance with the 5.1 Scheiner mix from Warner (and after that, expanded CD reissues of Astral Weeks and Band & Street Choir) so you have to feel like they were maybe in the running for the back catalog and didn't want to poke the bear - which is an almost impossible feat with Van given that every album he's put out since 1991 is basically an "old man yells at cloud" laundry list of all the people and entities he has grievances with - but figured they had nothing to lose once the back catalog reissue ...issue... was moot after the news of the Sony link-up.
Moondance was probably low-hanging fruit for an Atmos remix given that the multitracks were already digitized for the 5.1 mix, but given that the 2015 expanded reissues of Astral Weeks and His Band and the Street Choir both had session outtakes on them you have to hope that the multitracks for those albums also still exist, and that Warners (and Steven Wilson) will undertake Atmos mixes (and more grand-scale deluxe editions) of those two albums based (hopefully) on the success of the upcoming Moondance Atmos BluRay.