2: Process ARW using DxO PureRAW 5 and export as DNG
3: Process DNG using DxO FilmPack 7 and export as JPG
Testing the exported JPG in step 3 using DxO PhotoLab 9 confirmed that these two metadata fields were not missing and color rendering remained accurate.
It might sound like a daft question but, if you have PL9, why aren’t you processing your ARW files in that instead of adding two unnecessary external steps of PureRAW and FilmPack? PL9 already contains both PureRAW and FilmPack and you can open RAW files, edit them, including with the FilmPack which is integrated, and export as JPG from there.