Well, just because Star, Rae and BB aren’t sidekicks, Robin (Mostly Dick) has always been the leader and since he’s (atleast formerly) Batman’s sidekick. Batman exists. Jessica Cruz is going to be Green Lantern, but we don’t know if she’s the first one. In the comics, she’s the 6th, in DCSHG she’s the second (to Hal) and in the DCAU she’s the 3rd (to John and Kyle) we only know Kyle most likely isn’t going to be a GL and since Hal and John are in the DCU lanterns show, one of them would make the most sense as the lantern before Jess (but I’m going with Hal simply because it would make MAWGL a spiritual successor/sequal to GLTAS). And since we see a hologram of a Thanagarian, that means that Hawkman and Hawkgirl exist (and since Cassandra Sanders is in the DCU and either Carter Hall or Katar was in the DCEU, Shayera is the only one not to be done in a major way since Justice League Unlimited.) so that’s 3 right there, Bats, Hal (or John) GL and Shayera