I am having a hard time putting all the pieces together the way you are describing them.
Let's start with the totals and divide as we get headcount rather than get headcount first. Initial Flight to GGT (Georgetown Exuma) varies based on origin so we can figure that ourselves, estimate $500.
Charter flight total cost:
Please provide carrier information / quote for the plane options (6 seater, 9 seater etc) including landing fees etc.
4 passengers per vehicle w/ gear = 2 vehicles vs 1?
Lodging cost in total:
We can divide later when we know how many people.
I think we can safely estimate $100 per person for food where there is a kitchen and 6 lobster per person per day limit and maybe a grouper or snapper or two (license required to retain lobster / fish)
Gas is a factor - Long Island is 80 miles long and if we can't DIY effectively near Deadman's then there will be a long drive to start the day at Stella Maris (I will not be fishing with a guide). Maybe we should include additional pricing for lodging options on the north end, up to you. Boat rental is another way to go.
I will do same for the Acklins / Crooked estimates.