1dn: Composer is god if he changes ends (6) b?a?l?
5ac: Fight with Queen's violinist? (7) s?r????
7dn: Zoroastrian river piece (8) ??r???a?
8dn: Restore what may have been overeaten heartlessly (8) ??n???t?
12ac: City of 10's bird? (4) no letters [10 is Lohengrin, theme is Wagner]