I don't know about the NEO engine configured A321, but American is currently using the standard A321 in ETOPS on the H version. The H version is simply a company nose number designated for Hawaii flying. American is currently flying LAX -HNL in the A321H designation.
The H is added to alert maintainers that this aircraft is to be maintained under ETOPS standards. So far operations have been normal, except for the occasional weirdo trying to break onto the flight deck.