Backup singer Neal Matthews Jr., 70, who was one of the Jordanaires quartet (who sang with Elvis, Patsy Cline and Ricky Nelson, among others), died in his native Tennessee on Friday of an apparent heart attack . . . Alexander H. Cohen, 79, the colorful Broadway producer who brought the Tony Awards and the “Night of 100 Stars” specials to TV (Cohen’s last show, Noel Coward’s “Waiting in the Wings,” stars Lauren Bacall and is still running), died in New York on Saturday from emphysema.