Based on the discussion with @almostfinee who provided this YouTube link, I changed previously locked fields:
- I left locked the title "E=mc2", because this is on-screen title.
- Origin country can by either Ukraine or France, based on the original public release of the movie. I don't know where the movie was released first, so I set it to Ukraine for now (because Ukraine is apparently main producer while the French contribution was most likely by providing finance and release channels). It isn't locked though and can be changed should anyone find some more information about the original release.
- Origin language is a bit tricky in this case, but because the on-screen title isn't language specific and because all the rest of movie credits are in English (including "The End" at the end of the movie), I set the original language to English, but left it unlocked.