Possible Clues:

• 'West Side Story' composer
• Composer at the end of months playing tennis
• French dramatist rent Ibsen adaptation
• Conductor best in second half of Wagner, strangely
• South African poet, said to be a coming man
• French dramatist who knew how to conduct himself?
• Leonard - - , composer of 'West Side Story'
• Leonard —, US conductor
• Mass producer of inner tubes, not university trained
• Composer's important name changed a bit where the rubbish goes