Hello and welcome to the forum,
If I’m not mistakenly remembering Mixbox was implement by one person, on a personal build of Krita. Only because the Mixbox Github was apparently really simple to implement, so it was a test / proof of concept on a solo capacity.
It is awesome that you made the the lookup table from scratch, but I don’t really understand what part of Mixbox is licensed. It is important to check if making the code and tables from zero avoid the license.
On another note, you can also follow the development on integrating MyPaint pigment mode into krita.
I realized the spectral mixing of mypaint in krita
Cheers.