Not all of gospel music is the hokey back-porch thing you think of. It’s kind of the wrong stereotype,” said Grant Frederick, who attends The Baptist Church at McAdory, McCalla. But Frederick, whose favorite style of music is southern gospel, isn’t your run-of-the-mill quartet fan. He’s 17 years old and the pianist for 4given Quartet. Then there’s 80-year-old James E.…