Each year since 2010, LouFest has attracted top-flight national and international acts to St. Louis for a two-day, mid-September music festival in Forest Park — a nearby, less-hellish alternative to big-name festivals such as Lollapalooza, SXSW and Bonnaroo. But the prominence of LouFest’s headliners can sometimes obscure the handful of high-quality local acts lucky enough to make the bill.…