If anyone is interested in being able to edit/trade/release these legends, like we can the rest of the NFL teams during Play Now offline mode, then let EA know. Best way is to send them a Tweet. If they allow us to do this then we can effectively use these players for created teams. For example we can create the 1989 49ers with Montana, Rice and Young all on the 49ers. Or Aikman, Irvin, and Emmit together again.
I already tweeted EA but the more people who do, the greater the chances are that they will update the game to include it. And if you want other players like Marino let them know. On a side note. If EA created classic teams themselves for purchase as an addon, I for one would by them. Like the 60's Packers, 70's Steelers, 80's 49ers and 90's Cowboys. As long as they allowed us the ability to still customize them.
https://twitter.com/EAMaddenNFL