First is Harley Quinn, Joker's sidekick and girlfriend who's hanging out in Gotham.
Second is Helena Bertinelli/Huntress, also in Gotham.
Thirdly is Greer Grant-Nelson/Tigra, agent of SHIELD and a literal cat lady.
Last is Hal Jordan aka The Best Green Lantern. Since Hal has connections with Bart and Ollie and the rest of those Arrows, him and Wally need to be awesome together.