The dispute began in 2016, when Mr. Lombardo, a playwright, was preparing to stage “Who’s Holiday!” — a 75-minute, one-woman play that features Cindy Lou Who, the adorable girl from the book who teaches the greedy Grinch the true meaning of Christmas. In Mr. Lombardo’s version, Cindy Lou Who is all grown up. She is now a hard-drinking, prescription-drug-abusing middle-aged woman who lives in a trailer park and served time in prison for killing her husband, the Grinch.