I wish everyone were as conscientious as you, Bill. Nice to consider the probable future use of the room..but not necessary..just prudent.
Man, the small dimensions have me stumped! As for bonding the ceiling grid, seems to me that you still have to run your #8 to it, and rivit all the segments. Plastic light or plastic/glass trim for recessed light would work..since you can't get the required 7'6" from the high water level.
But the room dimensions..perhaps there is a building code requirement for the size of the room? Got to measure horizontally from inside the tub at least 5' to the switch and to the receptacle..can't cheat by going to higher elevation to increase the distance. Beats me!