A post from Tekken Nation details how fans of the Tekken series will be rewarded if they have save data from the Tekken Hybrid prologue pack. According to member FlyingWonkey, players with the data on their consoles will receive exclusive character costumes. Xiaoyu & Alisa will gain their schoolgirl costumes from the film, while Jin and Kazuya will be receiving their devil mode costumes from Blood Vengeance. Lastly, Shin Kamiya, a character exclusive to Blood Vengeance, will be an available replacement skin for Jin as well.
The post states that this pack will be exclusive to Playstation owners, though chances are that if this is true, that 360 players will eventually be able to shell out for it. Tekken Tag Tournament 2 will hit shelves and faces on September 14th.
Source: Tekken Nation