Good story with the life guard.
I wouldn't want the spool on the bottom because it will catch on other diver's lines. I wouldn't put a box in the float because I only use it for boat diving, obviously the articles you mentioned would be stored on the boat. And the float gets banged around quite a bit on a boat, the top of the pelican case would break for sure. When beach diving a float is not ideal, a board is a better solution. On a board there ample room to store a dry bag.
