Just a few years ago, she was reportedly executed by a North Korean firing squad. Now, Pyongyang's top pop diva is a senior ruling party official and a surprise headliner in the run-up to the South Korean Winter Olympics. Hyon Song Wol, the photogenic leader of Kim Jong Un's hand-picked Moranbong Band, has made two excursions across the Demilitarized Zone as a negotiator and advance team leader working out the details of Kim's surprise offer for the North to participate in the Pyeongchang Games. South Korea's media have been treating her like a true K-pop celebrity. On Monday, as she...