Sorry, I'm not going to be much help either.
AQHA hunters are distinct from other disciplines, including USEF hunters, with their own judging and conventions. And they are very competive.
You can start by looking at videos on YouTube, just search on AQHA Hunters.
My outsider's observation is that they carry a low headset and a little frame, headset not as low as a WP horse but lower than a USEF hunter, with the neck level or lower than the wither, that trot is a sweeping, flat kneed, forward trot, and the canter is slow and balanced but would NOT be mistaken for a WP lope.
I know we have members who show AQHA hunters on the board, I will try to point them to this thread for you.