I wonder if they'll release the characters in the same order as the silhouettes the released earlier. Which would mean Alex, Guile, Balrog, Ibuki, Juri, and then Urien.
Sounds sensible to me for a few reasons:
Alex was ranking very high in the fan favorite charts but wasn't present in STIV, so it makes sense not dragging it out any longer and just giving him to fans first. We also long knew he was present in the game in the background of one of the stages, so the surprise is long gone.
Guile and Balrog were just recently confirmed and they seem to be integral to the story that will be playable around June when the real story mode of the game releases. It makes sense to release them not earlier or later.
By then we have lotsa guys in the roster and a little variation with two consecutive released females would be welcome.
Last but not least there's Urien, also a fan favorite long not seen in the series. It makes sense that he's sort of the culmination of the DLC characters this year. Everyone will be really hyped for him. He also seems to be the ultimate boss of the game, so it makes sense to release him last, right?