System Grounding and Mixed Supply Grounding
Have single ground. Divede the board to domains (digital, analog, maybe something else) and place components accordingly. Those who have several supplies will then be on the boundaries between domains. This way no currents will cross those boundaries, so you will not have to separate grounds. Check what supplies will require separate plane (those with many comnections) others may be routed with wide traces on top or signal layers. 

Add chassis net on board outline, and bypass ground with capacitors to it. Two capacitors (0.1uF and 10uF) near each screw. So with metal enclosure all those points will be very silent. 

My impression is that in terms of supplies your board is quite common.