There's a location map here: http://www.myprivatevacation.com/Location.htm

You can rent kayaks here:

http://www.sailsportsbelize.com/

I don't think the water taxi goes that far south //ambergriscaye.com/download/ferryschedule.html

If you have 10 people you can probably do a discount with any of the operators. SUYA is the closest to where you'll be staying.

Rum, anywhere from $15 to $25 depending on what you buy and where.