Ok I've read through the entire post, please correct me if I'm wrong, but I did those steps:
1. One clean EU 3ds and one CFW (region set to EU), Two copies of the game (sun and moon)
2. I put moon game into clean 3ds, dumped sun save, and changed in pkhex, changed language to japan, also set region to japan and subregion to Tokyo. I did nothing on console side so it's still EU.
3. Put some japanese wonder cards, saved, moved save back to console
4. Got the mons with JAP mark and jap names, didn't check the region
5. traded over to clean game
Are the pokemons legal now? can I move them to home or i need to repeat step 2 and change console region to J ?