I just returned from LCBR yesterday, the water was 84 F and I just wore my thickest seaskin and never felt cold, but some folks were wearing light-weight wetsuits while others were in swimsuits and some were in heavier wet suits - so it is all about personal preference. If you tend to get cold then you should take it with you. Keep in mind that they also offer night dives twice a week if enough guests are interested and you will need to keep warm if that is of interest to you.
The diving is gorgeous and the dive boats will take you to the best sites available based on conditions. There was a Goliath Grouper posing for pics at the Eagle Ray Roundup site just 2 days ago (no Eagle Rays, though).
We were lucky and had great weather except for one day. The dive op always tries to make sure that the guests have great dive experiences and the valet diving is so easy.
Some of the hotel/food/dive packages include limited alcohol (mostly well drinks) and others do not. The drinks at the beach bar were usually around $7.50 US but specialty frozen drinks and some premium brands may be higher. I'm not a beer drinker so I don't know the cost of a beer but they had local Caybrew (light-colored beer) and Ironshore (dark beer) on tap and Heineken in bottles. There may have been other beer choices too, I am not sure.
There is a liquor store and a grocery store about a 10 or 15 minute walk from the resort (or a short bike ride) where you can pick up a bottle of liquor and some soda and mix your own drinks if you wish. You will see these stores on the ride in from the airport. There is a small frig in the guest rooms with an ice bucket and there is an ice machine behind the bar. A can of Coke costs $1.50 US at the resort
One nice thing about the LCBR is that all the prices are in $US so you will know what you are paying. That's helpful because the $US dollar is only worth 0.80 cents in Cayman money. Your resort fees include a gratuity for the staff but you may wish to tip specific staff that take care of you - it's up to you. The resort gratuity does not cover the dive staff and you should plan to tip your divemasters at the end of the week.
It's a fantastic trip, have a great time!
