Help with Questions to Moby-Dick: Is Ishmael a more mature and more profound version

Is Ishmael a more mature and more profound version of Redburn and Tommo as adventurer, narrator, and critic? Why is he the only survivor? How do his comments compare with those of Melville’s previous narrators? Does he seem to speak for Melville?  Where does Moby–Dick continue the themes of Typee or Redburn?