UPDATE: I just received an email from Mr. Penn and C&I granting me special permission to enter using my passport card on the 21st!

ecm56: Thank you again for the suggestion to email him. It worked like a charm!

Fitzhughlaw: I just got the card back in 2017 because I was being cheap and really had no intention of travelling anywhere other then Mexico, Canada, and the Caribbean. The TSA website sold it as the perfect solution for half the price of a book. Nowhere does it say anything about there possibly being exceptions to its acceptance in any of the islands. I assumed they had checked that all out before pushing this product. But, I am now definitely going to apply for a book as backup! Planning to travel down there again in July and don't need to go through this again.

Thanks again everybody for the suggestions and well wishes! Maybe I'll see some of you down there in two weeks during my triumphant return after a long 10 year absence and I'll buy you an adult soda!