Yes, Emmylou and Gram had a relationships. There are a few books out on Gram that talk about their collaboration.
Long Black Veil
Crystal GayleI do not believe that is a correct answer. Crystal Gayle is Loretta Lynn's Sister.Emmylou Harris was born in B'ham, AL
No, not as far as wikipedia is concerned.
Gram Parsons died on September 19, 1973 at the age of 26.