Complex sentence: The film's Executive Producers are Selby's wife Suzanne Selby and his last screenwriting partner Kenneth Shiffrin who was a writing partner with Selby on four projects including the screenplay, Scardust.
Split into simpler sentences: The film's Executive Producers are Selby's wife Suzanne Selby and his last screenwriting partner Kenneth Shiffrin. The other executive producer is Kenneth Shiffrin, who was a writing partner with Selby on four projects including the screenplay, Scardust.