I have to ask - you keep mentioning words like "irrefutable", "discovery" and "investigator" - yet you mention you have not been given an opportunity to inspect the engine.
So - who told you what about the engine condition?
Just like James tried to explain, the trajectory fully supports NTSB's findings, we would all like to hear more where you heard about this "power turbine wheel" failure?
Also, you say "Since he had power, he made the right bank and continued to accelerate to over 150 kts. At some point on that bank, the engine completely lost power and he tried to keep his pitch up but was only able to get to negative 2 degrees." - this is completely implausible. At 150kts you have a massive amount excess energy you can convert to altitude. I'm not a Caravan pilot, but I assume you can gain 300-400ft easily before stalling. This too supports the fact, that engine was fully functional until the impact.