Well, of those three, 'Ohana doesn't have Mexican food, and Coral Reef doesn't have Mexican food, so if you want Mexican food, I'd go to the Mexican restaurant, which is San Angel Inn.
What kind of Mexican food do you like? San Angel Inn serves traditionalMexican fare (think mole sauces, etc) versus what is touted as Mexican food in most of the U.S. (think fajitas, chimichangas, flautas, etc). Make sure you take a look at their menu to see if it is the style of Mexican you like.