The voices behind the characters of “Moana” livened the Oscar stage on Sunday night, with “Moana” actress Auli’i Cravalho and one of the film’s music writers, Lin-Manuel Miranda , performing the Academy Award-nominated song “How Far I’ll Go.” Miranda, who Dwayne Johnson introduced as his “twin,” rapped an original prologue before Cravalho, 16, took over singing duties as dancers — clad in blue attire — brought the film to life on stage, creating an oceanic look with scarves.