Well, as I previously showed in my recap way back when, Barbara Gordon (and Bette Kane) both exist in the Young Justice Universe.
And here's Bette, talking to Rainbow Das- I mean Artemis.
And even as of January 30th, the show's producer Greg Weisman has been particularly hard on revealling if Barbara will be appearing as Batgirl in the series,
And as for Bette being Batgirl: HAHAHAHAHAHA... no. Not going to happen.
But the fact that whether a Batgirl'll be in it or not is considered to be a spoiler, could be an implication that there will be one in the YJ: Invasion mini series at some point or another.
And a toy that they've released seems to suggest that this might be likely,
DCWKA seems to think that it's Barbara as Batgirl there, but really, I know that this is probably kind of expected of me by this point, it actually looks like a different and totally unexpected Batgirl all together's costume...
From Batgirl Secret Files,
Steph meanwhile has to make do with a semi-cameo (with a spiffy hat) in Friendship is Magic,
Ce la vie.