Well considering Corporate Luthor is the only one who counts.
In what sense? Luthor was an evil scientist/inventor for the first 45 years of his existence as a character; the corporate persona is only 26 years old to date. And of course screen adaptations are free to reinterpret the character however they wish, drawing on multiple prior influences; the Luthor of
Superman: TAS was initially just the corporate version, but he was later revealed to have the scientific brilliance of the pre-Crisis version, and in
Justice League his corporate empire was brought down and he reverted to his overtly villainous evil-inventor persona, subsequently taking a season-long swerve into his politician persona from the comics before ending up back in full-on Legion of Doom mode. (And of course the
Superman Returns version was a wholesale resurrection of the lame version from the Reeve movies, the aspiring land mogul with idiot henchmen.) So if we're talking about the possibility of Luthor's appearance in a JL film, there's no guarantee that the film would favor only the corporate interpretation; indeed, I think if you want Luthor to be a JL antagonist, you'd pretty much have to make him a more direct physical threat rather than just a corrupt businessman.
Besides if we want to look at Superman and how he would appear in a Justice League movie pretty much everything prior to the reboot is probably out.
There is no reason whatsoever to assume that. Again, adaptations are always free to draw on elements of whatever interpretations they want. They've never been required to conform slavishly to whatever is currently going on in the comics -- since, after all, the number of people who actually read the comics is tiny compared to the moviegoing audience, or even the TV audience. Usually, screen adaptations of comics borrow from many eras, not just the current one.
Batman: TAS was required to draw some stylistic cues from the Burton movies, but storywise and character-wise it drew on Batman comics from the '70s, '80s, and '90s alike.
Avengers: Earth's Mightiest Heroes has been drawing on story elements from throughout the decades-long history of the Avengers, mixing them together freely. And the live-action Marvel movies are freely mixing elements of the original and Ultimate universes.
