Eagle: Teased at during Comic Con and full reveal at Evo. Will be in the beta. Not playable at Evo.
Ken: Reveal at Evo. Will be in the beta. Not playable at Evo.
Akuma: Teased at Evo and full reveal at GDC
Si-won (NEW): Korean Hapkido grappler, reveal at GDC
Karin: reveal at TGS
Dhalsim: reveal at TGS
Sabrina (NEW): German femme fatale, reveal at TGS
Urien: reveal at TGS
Lucia (NEW): Dive kick character from Final Fight. reveal in October around GDC China and Brazil Game Show time
Juri: reveal at Capcom Pro Tour Asia finals
Sakura: reveal near Dreamhack Winter dates
Alex: reveal at Capcom Cup
Guile: reveal before launch
Zephyr (NEW): Boss character, reveal before launch
Akira: From Rival Schools, planned as pre-order DLC. Will be the first DLC character which will be added in periodically, no price point but probably around $6 if you don't pre-order. Announcement will be made sometime after both betas have ended.
Vega: DLC character to be released with Akira. No price point but also looking like $6.
This list seems more believable than the first one, although Ken got revealed now instead of EVO. Wonder if this Si-won character was the teaser in Ken's video.