Chef's Back, Even If Hayes Isn't 'South Park' premiere trumpets character's return March 20 2006 LOS ANGELES -- "South Park" creators Trey Parker and Matt Stone may yet have the final word on Isaac Hayes' departure from the show. The series, which has been the focus of much media speculation in the past week over Hayes leaving and Comedy Central's pulling of a Scientology-mocking episode, begins its 10th season Wednesday night with an episode called "The Return of Chef!" -- while making no mention of Hayes. In the episode, Chef makes a "triumphant homecoming" to South Park (even prior to...