I know that Billie Hayes took over for Charlotte Raye on Broadway. I'm not sure if Leslie Parris did the same for Edie Adams.
Actually, there's a story behind Billie Hayes and Charlotte Raye. Charlotte Raye had already signed her contract to play Mammy Yokum when the producers saw Billie Hayes in another show and decided that she would be perfect for Mammy Yokum. The producers tried to buy Raye out of her contract, but sensing that "Li'l Abner" would be a hit, she wouldn't budge. Not getting what they wanted the easy way, they decided to make Raye want to quit. They took away her song, cut down her part (as much as you can take Mammy Yokum out of "Li'l Abner") and, I think, they even took away her dressing room. She had to dress with the chorus girls.
But, Raye stuck it out until the end of her contract. And then the producers hired Bille Hayes for the rest of the run and the national tour.
I discovered the show when I set the timer on my VCR to record it on TBS in the middle of the night about ten ago, basically for the rare/camp value. And when I watched it, I fell in love with it!
The show stands up so well! (I mean, who here actually remembers reading the "Li'l Abner" comic strip!) The opening number has to rank up there with "Tradition" from "Fiddler on the Roof" and "Comedy Tonight" from "A Funny Thing Happened on the Way to the Forum" as one of the best opening numbers in terms of setting up the tone and characters of the show that you are about to see.
"A coherent existance after so many years of muddle" - Desiree' Armfelt, A Little Night Music
"Life keeps happening everyday, Say Yes" - 70, Girls, 70
"Life is what you do while you're waiting to die" - Zorba