Johns knocks Canary out of the original JLA, because making her a founder is a bad icky retcon building up some girl he doesn't care about, trying to give her something on her resume since her Golden Age adventures have all been given to her mom.
But Johns makes sure to hammer home that Barry's mother is DEEEAAAD because that's a good retcon that he things is building up a character he claims to love (and Johns has recently converted Zolomonism, so he thinks you need tragedy in your origin to be a good hero).