Was just re-reading part of the third collection of the 2011 Action Comics and found this bit:
Thoughts?
This could be pretty key. A fifth dimensional being associates New52 Superman with the color red, saying his wish has to involve it. She also says he lost a big part of himself in the battle with the other 5th dimensional being that had unfolded, and there we see Superman Red and Superman Blue. Interestingly, within that arc, we also see Superman reference events that happened to the pre-Crisis Superman as if they had happened to him- the boxing match with the heavyweight champ, his death at the hands of Doomsday (Granted, this may have happened to new52 Superman "off-screen"- continuity is inconsistent on that point), etc.. He never references those events again.
Then we see in Rebirth, SuperDad is associated with the color blue, told he's not who he thinks he is, there's the glowing blue hand, Swamp Thing tells him he's out of sync with the universe and makes reference to blue and needing to become part of the universe, and we see the creatures trying to wipe out Supermen across the universe fail to recognize SuperDad as a Superman and go straight for the Chinese Super-Man instead.
I wonder if these events were set up as far back as the New52 Action Comics bit above. Has anyone asked Grant Morrison?
It all kind of fits with the "New52 Superman is Superman Red, SuperDad is Superman Blue, and both have to merge to be complete" theory.