Congratulations on this work, great idea and execution, I’m impressed!
To my understanding, sampler synth metadata can also set the reference frequency for pitch (other than A 220Hz which I think is the reference). See this thread https://op-forums.com/t/root-of-user-samples-in-synth/2017/3
It would be awesome if we could set the “root note” in your tool for the sampler synth manually!