Ok - Thanks for the update. Sounds like you got it covered.
If it was mine, I would start with a OEM set of rings and a piston and check the end gap. If the cylinder is in spec and no damages then that variable is out of the equation. The rings you have could be either completely worn out or maybe not even the correct ones. New set of rings - including the oil ring. See what things look like after you get them. You should look into the valves condition and see what you got also. Valve guides could also be contributing to the burning oil.
Good luck -
Life without Motorcycles would just be boring, really boring