Carnelle Scott is best-known in her hometown of Yazoo City, Mississippi, for her unrepentant promiscuity. An orphan taken in by her genteel relatives, she idolizes her older cousin, Elain Rutledge, a former Fourth of July “Miss Firecracker” contest winner who is taking time out from her life as a pampered wife in Atlanta to give a speech on “My Life as a Beauty” at this year’s …