Christa Del Favero held a rehearsal in her home for L’Opéra de Lafayette’s diva voices. Dorothy Slater, Sasha Massey and Hanna Mayo tuned up for their upcoming Lieder Abend in Wien at First Baptist. “A minor or G minor, your favorite first,” went the conversation around spinach quiche. Massey sings like an angel and German never sounded so beautiful, or anything else for that matter. These ladies are the ones to watch — and you thought you had to go to New York to hear the Met.