Will Superboy be in the Legion of Superheroes?
yup, he's there, but it appears there are current legal issues involving the character, so he could be written out in future episodes.
The Legion of Super Heroes is a group of teenaged heroes in the 31st Century. Confirmed regular Legionnaires to appear: Superboy, Lightning Lad, Saturn Girl, Cosmic Boy, Bouncing Boy, Brainiac 5, Phantom Girl, Timber Wolf, Triplicate Girl.
Cosmic Boy is voiced by Wil Wheaton, former child actor (
Stand By Me,
Star Trek: The Next Generation)