Broadway's magical fair lady, Mary Poppins (Ahmanson Theatre, November 13-February 7), will land in L.A. complete with the show's original New York stars, Ashley Brown and Gavin Lee. Laguna Playhouse Youth Theatre will presents Stuart Little: A Musical Fantasy (Laguna Playhouse, November 6-15), based on the book by E. B. White, and Colleen Neuman's The Princess Plays (Eclectic Company Theatre, through November 22) consists of two comedies featuring famous fairy-tale princesses.