No, the El Capitan March was a different march written by Sousa.

King Cotton didn't invent nothing because King Cotton was named after Sea Island Cotton....It was named Sea Island Cotton before they got the name King Cotton and there is your answer

Billy Cotton Band Show was created in 1949.

Billy Cotton Band Show ended in 1968.

John Philip Sousa got the nickname of the "march king" from the excelent marches he and the band performeed

p.s He was responsiable for in the Marine Bands greatness or excelencance