Why were the harbor pilots never interviewed?
How do you know that the NTSB did not interview the harbor pilots? Generally the NTSB is going to talk to everyone on the bridge and pull the recordings of the Bridge from the ship.
Since it was a short voyage, they will have a recording of everything from before the ship left the dock.
NTSB has interviewed both pilots, the captain, the mates, the deck crewmen, Chief Engineer, the other engineer officers and the engineer crewmen. Preliminary report due sometime in May.