Islander as turbo-prop? Coulda sworn the ones I flew in (PAX) were straight recip motors. BTW, to add to the fun, there's the Trislander - the prop/motor's high up on the tail. It can be tail-heavy (now there's a surprise) if not loaded right. A local commuter flew the Islander and Trislander. Sitting on the ramp, waiting to ...ah... de-plane, the ground crew seriously punted, took bags out of the nose compartment without putting the tail stand in place. The bags came out, the nose started up, someone literally draped himself over the nose to bring it back down, and we PAX said, "oooohhhh!" Hard to forget those fun moments.
Anyway, for ticky-tacky Tiki Air, stick with a clapped out DC-3, maybe, as suggested, a Grumman Widgeon, Albatross, etc. if the plane's supposed to get wet, or, the bush pilot's fave, the DH Otter and relatives, with or without floats, floats recommended for lake landings...
The Catalina / PBY is probably so (relatively) rare as to be closer to a museum piece. Pass.
Of late, even operations like Watermaker Air, between Staniel Cay, Exumas, Bahamas, and the US, have "civilized" a/c, quite ho-hum. Unless they're your a/c! Planes and salt sea air do not agree well! Strong spring into fall thunderstorms in even (Bahamas) large a/c are downright scary. Had an unplanned stop in Freeport that way. Eek!
Check out the landing sequence early in the movie "Club Paradise" (Robin Williams!) for an idea of island flying gone wrong.
HTH!