the 70mm is just a blowup of the standard 35mm. Yeah i know it came out first and was missing the Star Trek II tile card on the premiere prints but unlike Empire Strikes Back there are no differences in the film.

Wrath of Khan has been restored in 4k from its original negative. Only Paramount knows when the 4K disc will come out but the Blu Ray is the best the film has ever looked on home video. Even if i’m not sure how theatrically accurate the colors are, they are certainly different than the Lowry version.

It is Star Trek 1, and 3-6 that need 4k restorations.

As for there being a fan scan of Khan i don’t believe so in 35mm, for certain i’m sure none has been done. Some of the other films have. Though i don’t have those preservations myself.