User blog comment:Wondergirl130191/6 Leaguers on Rimbor/@comment-5145408-20120914055244

the people behind the show have mentioned that choosing those 6 leagures was intentionally a reference to the main cast of the Justice League animated show (with the exception of Flash who they said they needed him still on earth for a certain something that happens in season 2-- i don't want to say what in case you haven't seen that far yet).

As for if they will come back alive... the same episode that they went missing, they also show them coming back, so you might not have noticed that part... ?