An audacious what-if scenario lies at the heart of Regina King‘s poised, well-crafted but conceptually conflicted directorial debut, “One Night in Miami,” a high-minded drama that plays as an all-star real-life Black superhero team-up: What if newly-crowned World Heavyweight Champion Cassius Clay, singer Sam Cooke, NFL record breaker Jim Brown and a Malcom X on the cusp of breaking with the Nation of Islam, spent the pivotal night of February 25, 1964 sparring, bickering and mutually inspiring in a hotel room in Miami? It boggles the mind, but though it sounds like speculative fan-fic, it’s not a what-if at all: On the night of Clay’s first defeat of Sonny Liston, the four men, all friends, did reportedly gather at the Hampton House Hotel in Overtown, Florida. So “One Night in Miami”‘s what if is a different one: what if the conversation between them had somehow been recorded for posterity?