1.) The story with Croc and Joker teaming up did happen. That part did and Vale's breakup with Bruce Wayne. Those stayed the same.
2.) But Croc never killed Jason's parents. Because DC is keeping the post Crisis explanation going that Jason was an orphan from Crime Alley that boosted the Bat-Mobile's tires.
I really wonder if we will see Nocturna/Jason brought up where she tried to adopt him. Or if that too has been pushed on the "retcon , never happened" deal.