The Tales of Festival website has updated their guest list, announcing performances by Deen and Bonnie Pink on June 15th and 16th respectively.
Deen has done the opening theme songs for Tales of Destiny ("Yume de Aru Youni"), Tales of Hearts R ("Eien no Ashita") and Tales of the Rays: Fairy's Requiem ("Mirai Kara no Hikari"), while Bonnie Pink has done the opening theme songs for Tales of Vesperia ("Ring a Bell") and Tales of Asteria: The Land of Crystal and the Guiding Light ("We Belong").
Currently, the Asobi Store has finished its Premium and SS ticket lotteries. The next set of ticket sales would be lotteries for S and A tickets in various ticketing websites. You can find more details on the Tales of Festival official website.