Yes there is the Akuma one but we don't know when that occured, whether it was before the finals or afterwards or what.
We know from Ryu's speech in SF3 that he likely fought Dhalism at least once during the tournament hence his comments to Necro.
Dan? Well I suppose if Sakura was in this game, then he should be in it as well, I forgot if they made this official or not but in one of the manga's, Sakura basically uses him as adult so she can track Ryu down. According to Karin's Z3 info, she lent Sakura her jet at one point and possibly battled her in Thailand after their confrontation with Vega, so I doubt it.
Lyn and Mel aren't even 12 or so by SF3, I think. Wouldn't it be stretching it to put them in? I could see Guy or Cody again before them. Maybe even Eagle or Rose.