So just to make things clear: New 52 universe is the Post-Crisis Universe with 10 years stolen, plus being merged with Wildstorm and Vertigo? And the memories that Wally is giving out are the memories that were lost which
"erased"?
It is not that simple, and no one is addressing it directly. It cannot be just post-crisis universe minus 10 years. Things happened differently. A new Kid Flash, a different original Teen Titans, totally different New Titans, Cyborg is still a JL founder (and the JL origin is tied to Darkseid). That is not post-crisis universe.
My take is that it is a new timeline post Flashpoint, but that timeline was messed up by Manhattan, compressing the events which out be more similar to post-crisis if that 10 years wasn't stolen. I.e. people remenbers Wally now, but are their memories the same as Wally have?