Well we know it's an island but we don't know the physical make up. So let's assume similar to Block. Varied shoreline beach, rocks, boulders, cliffs, etc...
Limiting it to just four is going to be tough six would be better but here's my four.
1) a blue over white danny (Beachmaster, Tattoo, RM Smitth, MAC, etc..) very versatile as mentioned by bending the eye and fchanging the retreive can cover the surface and subsurface, that covers my meatl lip
2) a white bucktail jig (Andrus) w/ a curlytail trailer and a casting egg to use as necessary to increase it's versatility in certain locations/terrain/structure/conditions
3) a parrot pencil
popper (Hab's) which I feel is a very versatile surface plug
4) a white or black 2 oz
needlefish (Hab's) ideally would have several colors and sizes
My other two if it were 6 would be
5) a black surf hog or
slug-go
6) chicken scratch bomber
hard to leave
tins out so they would be next should the list go on