Basically what you have illustrated is that an airplane of conventional configuration is more stable with a more forward cg and less stable with a more rearward one. Less stability is desired for an aerobatic plane and a little more stability is desired for a trainer. (The more stable in pitch, the more tendency to “balloon”) You are absolutely right.

As regards lifting tails, a tail with a cambered airfoil shape (referred to as a “lifting” tail) was all the rage in free flight models in the 50’s and 60’s, but the reason was different. The model was trimmed to glide at the minimum sink rate angle of attack but had to climb under power at a lessor angle to gain the maximum altitude during the limited engine run. Since there was no control once the plane was launched, many schemes were tried to make the transition work. One of these was the “lifting” tail. The flat bottom airfoil section of the stabilizer was in the slipstream of the propeller and it was thought that the increase airflow across the tail would “lift” the tail when the engine was running, reducing the angle of attack of the wing, and allowing a more efficient climb. Many contest winners of that era had this configuration. The incidence was such that in the glide the force on the stabilizer was nearly neutral or even down.

If the cg is moved far enough aft (on an airplane with typical sized tail surfaces) to require lift at the horizontal stabilizer, it may be in balance but will likely be unstable.