Hey! Welcome to our little forum! I would definitely recommend using a travel agent or a travel group. Using one of those type groups will definitely help because they can get a block of rooms for your group, group rates, etc. Then once you've booked Azul Fives, you'll get assigned a wedding coordinator who is with Karisma properties who owns the hotel. The coordinator will be based out of their Miami office, but will get everything set up for you for the wedding. Then when you get to the hotel for your wedding, the on site coordinator has everything from the Miami coordinator and takes care of you from there. Since most of your guests will be traveling from NJ/NY area, I would say it'd be best to use a travel agent or destination wedding travel group. I don't know if any travel agents will actually coordinate your wedding for you. Other people may know that.
Also, since June is a relatively off peak season travel month, then you should be able to keep the costs down. Our wedding for 110 people is costing us about $17k for everything at the resort (ie food, decorations, rehearsal dinner - which we got included b/c of our group size, welcome cocktail party, post ceremony cocktail party, reception, etc.). I think with your size group you may be able to get some events free.
Hope that sort of helps. Sorry if I sort of rambled. I'm not an expert on the hotel so other people on this forum could definitely have some other ideas and suggestions for you.
PS - I'm super impressed you're taking the lead on this stuff. Your fiancee is lucky!! It's a lot of work.