While pork and seafood (especially shellfish) are at the top of the list of food items that one does not serve without notifying one's guests, I do not see the AHA posting a menu of choices ahead of time. I can see how giving people entree choices could be a nightmare at NHC scale. I am fairly certain that there are times when a planned item is not available at NHC scale, and a last minute substitution has to be made to the menu. It is easier to address the outliers.
My advice is to order a vegetarian or vegan meal if there are any animal products that one will not eat because the NHC banquet is like a box of chocolates. I eat a mostly plant-based diet (i.e., what is known as a flexitarian diet) for various reasons, so I am cool with a vegetarian meal. The AHA is also attempting to accommodate dietary restrictions; therefore, if anyone has religious, food allergy, health, or simply "I would rather starve than eat" dietary restrictions, now is the time to speak.