Jason “Jay” Russell never set out to become a rock star. That may be the clearest way to understand his brief, essential place in the story of For Squirrels, the Gainesville-bred indie rock band whose promise, work ethic and tragedy became part of Florida music lore. Jay was there before the record deal, before the national attention, before the band’s devastating 1995 van crash, and before its major-label album Example reached listeners who would never get to see the original lineup realize its future. He was there when the songs were still raw enough to arrive on a cassette tape,...