Yeah, II and Alpha and probably IV would have “extra packs”.
5 extra characters per chapter looks like a good deal.
“Extra Alpha” pack could be Gen, Rose, Sakura, Dan and Ingrid (she debuted on Alpha 3 MAX). I wouldn’t be surprised if Sakura makes it into the initial roster instead of Karin, though.
“Extra II” pack: Guile, Akuma, Fei Long, Blanka and Balrog (assuming Sagat and Dhalsim are the last two in the initial roster). Akuma would be an unlockable boss or something.
Rolento, Sodom, Cody, Guy and Haggar could be the **Final Fight **pack.
Alex, Urien, Dudley, Ibuki and Sean/Necro/Makoto/Elena/Oro for the Street Fighter III pack.
Juri, Rufus, Abel, Viper, Gouken and for the “Street Fighter IV” pack.
But of course they’re not adding everyone there. Wouldn’t be surprised if there’s no Final Fight pack and we have Karin, Dan, Rose, Guy and Cody instead as the “Alpha pack”.
Or they will just have 3 more characters per “chapter” and that’s all (like III: Alex, Ibuki, Dudley; IV: Juri, Abel, Viper; II: Balrog, Sagat, Guile; Alpha: Dan, Sakura, Rose; Final Fight: Cody, Guy, Haggar).
There will probably never be a “Street Fighter One” pack, since Capcom prefers to pretend it never existed and the Street Fighter II and Alpha chapters have “absorbed” those characters instead…