I remember that thread.
The thing with the Superman movies is that there were adaptations done in the past. Not of the first two Superman movies, but of III and IV. The first two movies were under some restriction--I think it had to do with Mario Puzo having written the original screenplay for both (although a lot of that was completely rewritten for the movies).
I'm guessing those restrictions no longer hold. I think the whole Puzo thing also caused a problem with Brando (they were a package deal) and as a consequence his scenes could not be used in SUPERMAN II. But since those scenes have been used in the restored Donner cut of SUPERMAN II and in SUPERMAN RETURNS, that would suggest that the Brando/Puzo restrictions no longer apply.
When SUPERMAN THE MOVIE was cast, the AMAZING WORLD OF DC COMICS No. 14 pointed out the similarity of Chris Reeve to Curt Swan's Superman: https://myfavouritefunnies.files.wor...smtreport2.jpg <--this is posted on my extra blog page Another You Revue--more about that there.
While I know John Byrne took some inspiration from the movies, I don't really think his Superman looks anything like Reeve. And he certainly contradicted a lof of the elements in those movies.
DC also adapted the SUPERBOY TV show. I realize that show isn't exactly in continuity with the movies, but the Salkinds intended it as sort of a spin-off from them. As well, I thought that Tom Welling looked a lot like Christopher Reeve--more than Jeff East.