Drop Down for a Base Hit

Holy cow, this puzzle is missing the given letters. It's a good idea solve those first.

  1. Does like a straw + an average grade
  2. Matthew's successor + Short greeting
  3. Greek rainbow goddess + First word of a soft drink name
  4. Split
  5. Scale from 1 to 14 + Letters between 'O' and 'I' in a famous mnemonic
  6. Stone ___
  7. Second word of a soft drink name + 18th letter
  8. Author Kenzaburo + Author Kenzaburo
  9. The elbow or knee, minus the vowels
  10. Used an oar
  11. Rapper of "One Mic" + Letter that sounds like sheep
  12. Dr. of rap + Mr. of movies
  13. Fire hydrant attachment + Network with exclamation mark
  14. Male title, in Mexico, for short
  15. Like sharps and flats on a piano
  16. Animal housing + Square root of -1
  17. Mayo ingredient + Beyonce's husband, phonetically
  18. Binary five + Type of force
  19. Bonnet occupants
  20. Stomach muscle

Just solve the drop quote; not much more here.