Hi Fred,
The D2X/D3/D4/D4s do have flash compensation buttons:
It is number 57 on the diagram!
As does the D5:
Button 4 down on the left hand side! The D500's is in the same position.
The D500/D5/ will give the option of (with suitable strobes) giving TTL with flash output control, via that rear button.
I am unsure what you are asking:
How you would even be able to link an underwater strobe to the camera and shoot TTL may present new problems to the strobe makers since as far as I am aware, radio signals do not transmit well underwater.
The D500 can trigger strobes electrically and via the many electro-optical converters that exist. Some of these do not work via TTL, so this may present a challenge given your shooting style.
Your slave strobes, although they are wireless, are actually being triggered optically 
All the best
Adam
