On Jan. 7 the Palacio Valdés de Aviles, Spain is set to premiere “Diva.” The new show, by Albert Boadella, tells the story of Maria Callas and her relationship with Onasis. The show will feature soprano María Rey-Joly and tenor Antoni Comas as Callas and Onassis. Manuel Coves will conduct the work, which will also be performed between Jan. 14 {…}