Scott Elmegreen and Drew Fornarola’s lively satiric musical Ghost of John McCain has a throw-anything-at-the-wall feel to it, but it’s apt: the action takes place inside the mind of President Donald Trump between Aug. 25, 2018 (the date of John McCain’s death) and Jan. 6, 2021. Given the attention span of the ex-President, it’s no wonder that events in his mind carom around like billiard balls.