Aft of CG is correct. It lowers the drag...
Concerning the stator. I guess you are talking about engine...
They are of course convergent.
The 2 basic elements of the turbine assembly, stator and rotor.
The stator, or turbine guide vanes serve two functions.
The first function is to discharge the gas at as high speed as possible. The vanes accomplish this because the individual blades are contoured and placed at such angle so as to form what is effectively a series of small nozzles.
As the air flows through this restricted area, a portion of the gases heat and pressure energy is converted to kinetic energy that is further converted to mechanical energy when the air passes over the rotor blades.
At the same time, because the turbine guide vanes are set at a specific angle, the second function is accomplished, which is aiming the gas-flow at the rotors in the most effective manner
(source taken from "Advanced Aircraft Systems" by David Lombardo).
Hope it answers your questions...
Cheers.