Elsa is a ROUND character because we see more than one side of her personality. She is innocent and carefree, but we also see her stubbornness during the movie and her willingness to suffer alone in order to prevent hurting Anna or others.
Elsa is also a DYNAMIC character because she does undergo huge personality changes throughout the movie. At the beginning , but Gru's morals, values, and personality completely change by the end of the movie.