I think Luke Starkiller played an Obi-Wan-like role in the original Star Wars. If that's the version that got made on Earth-19, maybe he says something like what Cisco said with the whole, "we need you" spiel.
Since commencing his writing process in January 1973, Lucas had done "various rewrites in the evenings after the day's work." He would write four different screenplays for Star Wars, "searching for just the right ingredients, characters and storyline. It's always been what you might call a good idea in search of a story." By May 1974, he had expanded the film treatment into a rough draft screenplay, adding elements such as the Sith, the Death Star, and a general by the name of Annikin Starkiller. He changed Starkiller to an adolescent boy, and he shifted the general into a supporting role as a member of a family of dwarfs. Lucas envisioned the Corellian smuggler, Han Solo, as a large, green-skinned monster with gills. He based Chewbacca on his Alaskan Malamute dog, Indiana (whom he would later use as namesake for his character Indiana Jones), who often acted as the director's "co-pilot" by sitting in the passenger seat of his car.