I just read an post the states that two universes can occupy a designated world at the same time IE the how the JUst and Young Justice are both Earth 16 with Young Justice being Fictional on the JUst's version of the World and I assume Vice Versa. If that's the case what does Nuperman and Superdad combining due to each others worlds. Could this be why Pre-Flashpoint Earth 1 elements are Bleeding into the New52 Animated Universe like Doomday's sudden appearance and Ma and Pa Kent being Alive? This would go a long way to giving a cause to the sudden shifts in attitudes and Pre-Flashpoint characters suddenly popping up like they've always been there.
http://blanddcheadcanons.tumblr.com/...-dc-multiverse