3D is both controlled stalled flight and near zero airspeed flight - nothing more.

Aft CG, extreme throws, monster power, etc. refer more to what specific planes need to 3D. This really has nothing to do with the description of 3D flight. My "3D" plane has a very normal CG and I have reasonable (30 degree) throws, yet it 3D's just fine. Setup will really depend upon the plane. Aft CG will depend upon the plane design. In general, I think the only universal 3D setup is one needs more power than weight and controls that provide enough authority to control the plane past the stall.

AOA really only applies in forward flight, but for the most part that is correct. In a TR, one could say the AOA is actually zero as the flight path of the plane (up) produces a AOA of zero on the wing. A better description of a TR is then very low airspeed flight not high alpha. But that is probably splitting hairs, but thought it should be pointed out.