“The battle for the succession has been fierce in recent years, but the frontrunner is now Wolfgang Wagner’s chosen heir, his 28-year-old daughter Katharina — great-granddaughter of Hitler’s favorite composer. Yet it remains uncertain when or whether she will take over as director of the Bayreuth Festspiele, which closes on Monday night for the season. Her strong-willed father may not give up the post or another might still seize the crown.”