It's not a big surprise you get slightly different colors (+-1 per component) comparing Hi444PP with YV12. Otherwise what would be the point of 444 10-bit encoding?
In mpv you'll get 420 10-bit instead of YV12.
Thanks, I tried MPV but the lack of GUI makes it very hard to use/configure. If you could share some config file that I could copy and paste to get the best quality possible similar to what you get using madVR that would be of great help.