The Handel and Haydn Society will conclude its 2018-19 season with a performance of Mozart’s final masterpiece, “Requiem.” The program is also set to include Mozart’s intensely emotional “Masonic Funeral Music,” Allegri’s “Miserere mei, Deus,” which “captures the profound sadness, weight and power of the Passion story,” and Bach’s motet “Singet dem Herrn.” Featured vocalists will include soprano Joelle Harvey, {…}