I don't mind the idea of Chewie appearing in Ep 3, it kind of works for me that Obi -wan and Chewie knew of each other before meeting in the cantina, it was almost as if Obi-wan knew exactly who he was looking for, when searching for passage to Alderaan, and considering the legendary loyalty of wookiees and the urgent secracy surrounding the Jedi, Vader and his childrens identities, I can understand how Chewbacca could have kept this knowledge from Han in later years as his co-pilot.