Benito Cereno, borne on the bier, did, indeed, follow his leader.
I don't know whether or not Melville intended for the "leader" to be ambiguous, it could be Babo or Aranda. It's also worth noting that Babo's head is positioned to be looking toward Aranda's bones and Cereno's monastery. During my first reading, I thought this gesture served as another cruel reminder to Babo and other slaves of where they stand in the world, always looking for the white man. But as I read this again, I view it more as Babo taunting both men he had successfully destroyed, physically and mentally, even if his revolt failed, he remains tied to Cereno, a fact that haunts the Spaniard to his grave.