It's not really clear that there's any relationship between the moon being full and the pumpkin emerging. In fact, your full moon being set against a tropical island paradise removes all of the werewolf connotations. We need clouds, mountains, trees!
That's completely arbitrary, of course. There's no reason why a werewolf shouldn't transform on the beach. It's just become tradition that these other elements be in place to build dramatic tension -- the moon needs something to hide behind until just the right moment...
Anyway, whatever story you decide to tell, make sure we can all understand it without requiring a verbal explanation.
(that's not a prerequisite for "art", but it's absolutely crucial for "comedy" -- if we don't get the joke, you wasted a lot of effort telling it.)