I know that they will work with you on you meals, I would suggest contacting the resort directly prior to arriving and then meet with the chef when you get there about the food. As for beer I would doubt it, there are very few gluten free beers out there and I am sure that the cost to import them to Jamaica would be very high.
I have a few food allergies and we have been to CSA three times. The first two times they were very good about accommodating me but in Oct it was a battle. I'm not sure what changed. I wasn't asking for anything to be replaced, just removed. I can't have fish, seafood or shellfish so I asked if I could get the shrimp quesadilla plain (without shrimp) like I had last time. That was one of the things I was really looking forward to because it was so good the previous trip. They said they could not do that because it comes with the shrimp on it. It was like that with everything I asked for even though I asked in advance. It was very confusing because I have had all these things before and I was under the impression that they made everything like that from scratch. Sometimes they would say it was fine ahead of time and then when we got there they were not able to make any changes to the menu. When we went to Patios there was usually only one thing I could eat on the menu because I have other allergies too. Feathers was out of the question. The Palms and the Cabana Grill provided the bulk of my meals. It was a real struggle to get them to understand that I had food allergies and make a note of it for the repeaters dinner. We called to tell them what all I can't eat and they said I would be fine. I can't have fish, seafood, shellfish, nuts of any kind, beef and a few other things. It was not going to be fine. Eventually they did make a note of what I could and couldn't eat and I did get something else but I was a little worried for a while since there are not options at the repeaters dinner. There were a few nights when my husband ate because I ended up not being able to order anything other than an appetizer or something and then I just went to the Cabana Grill on the way out. lol
I think your specific diet would be easier to accommodate because they have seen it before. I sort of threw them for a loop because of all the meats they usually serve, I could only eat two. Chicken and pork are in the minority there too since most people prefer something else. Gluten free is a pretty common thing and they probably have some go to recipes already. I would be surprised if they order gluten free beer though. Not only does it take forever for things to get there after they order it because they have to import everything, but it seems like they pretty much offer something else they already have when accommodating a specific dietary restriction.