Identify the Criterion

Game time! Identify what the things in each list have in common, and comment with the point of commonality or another suitable item.

ROUND ONE (ANSWERED IN COMMENTS)
My Fair Lady
Dirty Dancing
Karate Kid

ROUND TWO (ANSWERED IN COMMENTS)
"Early One Morning" (Traditional)
Boston - "More Than A Feeling"
Tenacious D - "Tribute"

ROUND THREE (ANSWERED IN COMMENTS)
Jack
David
Hercules