Greg Weisman did reveal their are LGBTQ characters in Young Justice. I will list them and why we know they are.
Aquaman(Kaldur’ahm): He is currently in a relationship with Wyynde
Wyynde: He is currently in a relationship with Aquaman(Kaldur’ahm)
Harper Row Harper wanted to kiss Halo even though she already had a boyfriend
Marie Logan She was able to be controlled by Queen Bee, meaning she is not straight. Her actual sexuality is not identified, but we know she is part of the LGBTQ community
Unconfirmed:
Halo: (Kissed Harper Row and is possibly non binary)
Thirteen: (is bisexual in the comics)
Batwoman: (has not been focused on, but in the comics she is a lesbian)
Wonder Woman: (is bisexual in the comics)
Poison Ivy: (was only in one episode, she may or may return in future seasons, however, in the comics she was bisexual)
Rita Farr: (is bisexual in the comics and might have had a fling with Marie Logan)
Anissa Pierce (she might become Thunder in season 4, in comics she was gay)
Cullen Row (in comics he was gay and had a crush on Robin)
Tupka, please don’t comment anything rude or backlashing towards my post.