6. Uncle Owen & Aunt Beru
Owen and Beru always seemed to know the whole story of Anakin Skywalker and in Episode II we find out why. Theres not really much to add to our understanding of their characters but you could speculate that they felt they owed something to Anakin given that he returned Shmi's body to Owen's father, Cliegg. Its a loose thread, where we are given very little to form the grounds of Owen and Berus acceptance of baby Luke in Episode III, beyond a distant sense of family connection. Also, it may have felt a bit tighter if Padme had suggested them as an option as Obi-Wan and Yoda never really got to interact with anybody on Tatooine but its all quite acceptable as it sits, I guess. Of course, the biggest knock on effect of their introduction in Episode II is giving us a reason why Anakin/Darth Vader would not ever stumble across Luke on Tatooine. And its because his mother died there and he really has no reason in the world to go back to a planet that holds such terrible memories for him. A big theme for Anakin is his inability to deal with his problems and avoidance is always seen as a better option for him after all. We basically discover that the choice to hide Luke there was a logical one and they didn't even feel the need to change his name from Skywalker to, I dont know something common like Antillies or 'Lars' or something, as his father wasnt going to venture to the dust bowl planet anytime soon.