Board Thread:Young Justice News/@comment-1038387-20130219165616/@comment-3095612-20130326010609

To clear things up, Mr. Weisman only hinted Legacy may help clear up why Cassie Sandsmark was chosen as Wonder Girl and not Donna Troy.

Unrelated to Legacy, both Donna Troy and Mary Bromfield were originally going to appear in the season two episode "Satisfaction" but were cut. Both Donna and Mary were on the Team as Troia and Lieutenant Marvel (at least it's speculated Mary was Lieutenant) during the 5 year skip but left for unrevealed reasons. Mary Bromfield was also slated to appear in the tie-in comic but there was a mandate to speed up the storyline to the Invasion timeline so Issues #20-25 were made and the Marvel Family story that would have introduced Mary along with Freddy and Kit Freeman was shelved.