Fanny: A Fantasy in G, Tim McGillicuddy’s new play presented by Off-Brand Opera at the Gural Theatre at A.R.T./New York, tells the story of Fanny Mendelssohn — composer, woman, Jew, sister of Felix — and her lifelong struggle to claim her voice in a world not yet prepared to welcome it. McGillicuddy neither sensationalizes nor reaches for false modern parallels. He simply shows what happened, in a parlor, at a piano, over the course of a life. That discipline is the play’s gr