We talked about Cash and Jewel. Here's a full analysis of Faulkner's selection of characters' names. Interesting stuff!
And how about this amazing quote from Faulkner himself:
"Darl was mad. He did things which seemed to me he had to do or he insisted on doing. His reasons I could try to rationalize to suit myself, even if I couldn’t rationalize his reasons to please me I had to accept the act because Darl insisted on doing that. I mean that any character that you write about takes charge of his own behavior. You can’t make him do things once he becomes alive and stands up and casts his own shadow. Darl did things which I am sure were for his own mad reasons quite logical. I couldn’t always understand why he did things, but he did insist on doing things, and when we would quarrel about it, he always won, because at that time he was alive, he was under his own power" (Wiley).