“Boney Manilli” is retelling an age-old story from new perspectives. Loosely inspired by the infamous scandal involving pop duo Milli Vanilli, Edgar Arceneaux’s “Boney Manilli” follows the tale of two brothers – one who has struggled to finish his play about the late-1980s group and another who hopes to adapt “Song of the South” into his own play – as they come to terms with their mother losing her memories.