Misc: How many items constitute a baker's dozen?

Questions

Musical L: Pianist with the Modern Jazz quartet?

Musical L: She had a hit in the 50s with "Fever"?

Musical L: She sang "I need a man" & "I love to listen to Beethoven"?

Musical F: Country singer: "if youve got the money, ive got the time"?

What composer, at a performance of Handel's Hallelujah chorus, exclaimed "He is the master of us all"?