After being told that it cannot make changes to the licensed script for a musical it plans to stage next week, The Grand theater in Ellsworth is making a last-ditch effort to add Black actors to the cast. If it cannot find Black actors to play minor roles of two slaves in the musical, it will have to cancel the production, the opening of which has been delayed for a week, a theater official said. But in Ellsworth and other rural parts of Maine, the population of which is more than 93 percent white, finding actors of different races to...