I havent read the book, but I know theres one where Leia and Han (or Luke... somebody) goes back to Tatooine and do some research about Anakin. They find out about his mother, and Anakin's massacre and how that related to Beru and Lars.... honestly, I don't remember how that all worked out in the PT myself...
Is Lars still related to Obi Wan, or was that idea scratched when AOTC came out???