It’s “American Idol” at Spivey Hall, Metropolitan Opera style, for Southeastern finals February 6, 2012 By Stephanie Adrian Heather Phillips, last year’s Southeastern winner. (Photo courtesy HeatherPhillips-soprano.com) Lawson Anderson is a 25-year-old management consultant at PricewaterhouseCoopers. That’s his day job; on weekends he sings opera arias. As a high school athlete at the Westminster Schools in Atlanta, Anderson joined the school choir, where Scott Morris, then director of choral music, encouraged him to think more seriously about singing. “My mentors helped me to understand that there’s something special about singing, and I began to think more critically about how music…