What about the same situation considering an inverted stall?
Well obviously we would be talking about forward stick position.
I don't know enough to agree or disagree with you definitively! However, my instinct would tell me that CG etc. must have an effect on your theory, as it affects stability and by extension, the control authority available (regardless of how much control deflection is being employed at the time)...?
And your instructor would be correct when referring to the CofG. If you read what I stated I covered that point.
It's more likely that you can't do a true 1G stall due to lack of low speed effectiveness.
There may be one or two types, but in the main that statement is not correct. Care to name any types you know of?
There are types where the certification stall speed is defined as the lowest speed reached when you decelerate at 1kt/sec until you run out of elevator.
A speed reduction of 1kt/sec is used to determine the 1G stall speed simply to avoid distortion of the data as a result of increased G that would emanate as a result of using an increased rate of speed reduction. "Running out of elevator" is not a phrase that forms any part of the definition of STALL.