"An 'electronic replica' of a printed work apparently requires no additional rights even when contracts call for it."
This seems a little suspicious. I can guarantee that if I scanned, for example, every issue of The Amazing Spider-Man, put it on a set of optical media, and tried to sell it in a brown paper wrapper with no Marvel/Disney art, I'd still hear from Marvel/Disney lawyers.
Let's assume (wrongly) that I had an infinite wallet to pay for my own army of lawyers. Are you saying I could cite the NatGeo case and possibly win, as long as I restricted my sales to just electronic replica of the comics themselves? Even though Marvel has their own thriving digital comics business (see Comixology, Marvel Unlimited).
There has to be a catch somewhere. (Note to any Marvel/Disney lawyer out there bored and looking for something to do- I'm not looking to do this. Put the lawsuit down.)