Is this a new, "invented", way of looking at kyusho, or is this how the old masters really practiced kyusho? I think the best person you could ask is Taiki Oyata.
What evidence is there that supports that they did use a methodology that was linked to TMC and how far back does this evidence go? They use the same name an point location for each point an they use the same enegry flow.
Can it be traced back to the very creators of the karate Kata themselves?
I believe it can cause Oyata trained with some very famous martial artist that taught him. The fact he uses the Kanji an the letter names to study how an what something means is a strong point in knowing if it came from what source. The fact that the same approach is used even in Goju Ryu an Pangainoon an Uichi Ryu might give one open pause.
Were these points specifically addressed by the creators of the Kata so that the Kata specifically showed them?
No, cause it is still a gross physical movement. That is in a certain area of the body as a whole that cause slightly more damage.
Taika Oyata lives an teaches in Independence Kansas City area.