Great news to report! 18 days after initial lost, Norwegian Lost and Found finally sent me a message saying that they have found my passport. The cheapest shipping option (UPS Ground) is about $60 and the UPS Air is about $110. I assumed they surcharged some handling fees on top of the true shipping cost. I paid for UPS Air. They shipped it from Miami the next day and I just got it today! Thank you Norwegian Lost and Found!
Interesting that I didn't get back the envelope with some small amount of cash (<$100) that I left behind with my passport. I read from other posts that they may mail a check.
My lesson is that there is really no contact number for Lost and Found. Just fill out the form and wait. It takes about 20 days to get your items back.