Seeing that Sheik is in and that they're using an unused Twilight Princess design for the character really adds credibility to this site where I found an interview several days ago that said everything that was in this update.
Actually, I'm pretty sure Sakurai wants this game to have a lot of emphasis on single-player, as well as multi-player; he wanted to do the same with Melee, but Shigeru Miyamoto pressured him to do otherwise and focus more on multi-player.