User blog comment:Ankit09/Which Character should join Young Justice team/@comment-167456-20110319105302

What the source said is that Logan Grove has been cast as Garfield Logan (the idea that he'll be Beast Boy doesn't appear in the original source, only news sites that have picked up and run with it) and will appear in at least one episode. Logan Grove is really young, so I think the chances of him appearing as a regular cast member (let alone a member of the Team) are pretty slim.

Wonder Girl will definitely not be appearing in the first season, since there were legal issues when the episodes were being written that meant she couldn't be used. She may appear in season 2 if and when it gets picked up.