Here's a bit on that, FWIW [https://en.wikipedia.org/wiki/Teen_Titans_(TV_series)#Impact_on_DC_continuity]:I thought Teen Titans, and Justice League Unlimited were both part of the same universe?
Teen Titans has never been established to be a part of the larger DC Animated Universe or The Batman animated series. Series producer Bruce Timm stated the series would not cross over with Justice League Unlimited. Despite this the series was alluded to in Static Shock, which is part of the DCAU like Justice League Unlimited, where Static asked Batman where Robin was to which Batman responded, "With the Titans...You'll meet them some day." The character Speedy, who first appeared in the episode "Winner Take All", later appeared in Justice League Unlimited with the same costume design and voice actor (Mike Erwin) as the Teen Titans incarnation (though he is older in appearance). Kid Flash was voiced by Michael Rosenbaum in his appearances in the show, who was the same actor who voiced the Flash in Justice League Unlimited; both characters are the Wally West incarnations.
So, based on what I just posted, I'd have to say "very much no" to your "very much no." On the contrary, I think the situation is very much not established one way or the other.Wow, very much no.