I think the required GFCI on the light will make sure it is off if it leaks.
The location of an underwater light really doesn't make much difference in it's danger if it is leaking current into the water.
I doubt you can really get any of them out without getting in the pool. The minimum distance to the top of the light is 18" below the water's surface and that puts the screw more like 24-28" down.
