In Moses, a production of the Bavarian State Opera’s youth program and cast with a mixture of recent refugees, the children of immigrants to Germany, and native Bavarians, and set to “a mixture of new music by Benedikt Brachtel and adapted excerpts from Rossini’s Mosè in Egitto, the teenagers tell the story of Moses — common ground for followers of the Bible, Torah and Quran — with Brechtian interludes about refugee experiences and current events.”