The hero of "To Kill a Mockingbird"

I'm toying with the idea that the hero(s) of "To Kill a Mockingbird" is not Atticus Finch, but Boo and Sheriff Heck Tate. Boo strikes down Bob Ewell and Tate, over Atticus' objections, shapes the story of the killing to protect Boo. The evil, represented by Ewell, is untouched by Atticus' nobility and social conscience. It takes the recluse, the damaged man living outside society, and Sheriff Tate (who admits to Atticus that he "is not a good man" to kill and bury Ewell. Atticus' virtues can only protect the town and his children from the first mad dog.