You should get in contact with the weddings people. I just returned from a vacation at Cabo Azul and have decided to get married there. It was gorgeous!!!!!!!!
The hotel staff could give you an excel estimates sheet for you to work with if you are seriously considering having your event there. But yes that may not be enough. The alcohol consumption costs are a min. of $47.50/person and the food consumption (I'll have to double check on this figure) was about $65.00/person. We were crunching numbers with my fiance and we anticipate a wedding with 40 guests will cost us about $10,000 USD. But that's including practically everything.
Having looked at the place I can say it's EXCELLENT value for the money. And the food is outstanding. I can't wait to have my wedding there!
Maybe you should get in touch with the staff to discuss your options.
All the best!!!