During the pre-Broadway tryout, several roles were eliminated, but only two of them were played by performers who had no other roles in the show and whose services were therefore no longer required. Those roles were Polly Potter, played by Mitzi McCall, and Penny Potter, played by Clairborne Cary.
During the run, Eddie Gasper (an original cast member) replaced John Sharpe in the role of "George Musgrove (as a boy)," but Sharpe remained in the cast as well in the dance ensemble. Perhaps it was felt that Sharpe had outgrown the role.
In You Fascinate Me So: The Life and Times of Cy Coleman, Andy Propst quotes Neil Simon's memoir Rewrites, describing disruptive audience behavior at a performance of Little Me. Even though he's quoting Simon, Propst incorrectly says that the behavior described by Simon was said by Simon to have happened on opening night, but Simon in his book makes it clear that what he's describing happened at a Broadway preview.