Cyril and Libbye Hellier returned to the stage for the title roles of Humperdinck's "Hänsel und Gretel", for The New Opera Theatre, New Orleans. In the 1988-89 season, they alternated as Bastienne in the child Mozart's "Bastien und Bastienne" for the same ensemble. In the final season of The New Opera Theatre, they appeared in a Benefit Concert also featuring Natalia Rom. In April 1991, the Helliers were soloists in Part III of Handel's "Messiah" (in the Foundling Hospital Anthem version), at St Francis de Sales Cathedral, Houma. In October 1992, the sopranos made their New York debuts, as Kindred (Cyril) and Cousin (Libbye)
Moses und Aron about the number 13; "Moses und Aaron" has 13 letters. Zoltán Kocsis (Hungarian conductor, composer and pianist) had received permission from Schoenberg's heirs in 2009 to complete the last act. His version was premiered in concert at Budapest on 16 January 2010. As Schoenberg always intended to finish the work, the opera was not performed during his lifetime. However, the first public performance of music from the opera was of "Der Tanz um das goldene Kalb" in concert at Darmstadt on 2 July 1951, just 11 days before the composer's death. There was a concert performance of the two acts