Questions about moving pokemons and legality

[Cursed Wizard]

Hello, I am back again from my shiny hunting on old console and I have a few questions.

So I started hunting a shiny mew on emerald, today I finally caught it and after getting all the ribbons on emerald I plan on moving it to all my other games until the switch era.

Now here's the problem. I knew the mew from any emerald that wasn't Japanese would end up in an illegal shiny because mew was never released outside of Japan, so I downloaded a Japanese version of the to catch a legal one.

All seems rather fine until I started looking on how to move the pokemon to the ds era. My plan is to send it to a Japanese rom copy of soul silver with PKHEX or PKSM and then move it to my Italian copy of soul silver and move it up with no issues since I have all the games and bank. 

While looking on pkhex I found trainer date that wasn't showing in the emerald save file. The 3ds region it says it's Italian and the sub region as well, i understand that I used an Italian 3ds to play the rom but I didn't consider the data to be showing in later gens. Should I change it? Would it be an issue later on if I don't? I don't plan on bringing mew to tournaments other than using it online for some friendly matches. Would I be banned if I do? 

 

Any help is welcome, sorry for the long post.

[Soul DS]

49 minutes ago, Cursed Wizard said:

While looking on pkhex I found trainer date that wasn't showing in the emerald save file.

No date is tracked in the generation 1-3 games, since the gen 1 games + FRLG don't have any clock, and the gen 2 and RSE only keep track of days passing, not of specific dates. When moving your Pokémon to generation 4, the date of the transfer will be assigned (based on the date set in the DS, if done legitimately), and when moving it to generation 5, the date will be changed once more based on the date of the transfer to generation 5 (once more using the DS date): this generation 5 date is what is used for all of the games post generation 5.

49 minutes ago, Cursed Wizard said:

The 3ds region it says it's Italian and the sub region as well, i understand that I used an Italian 3ds to play the rom but I didn't consider the data to be showing in later gens. Should I change it? Would it be an issue later on if I don't?

When transferring Pokémon from generation 5 to generation 6 using Poké Bank, a country and region is set for your Pokémon based on what was set in your 3DS: since it's unrelated to the language of the Pokémon itself (you could be transferring English, Spanish, German, Italian, Japanese, French, Korean Pokémon independently of the region of your console and language of your game), this setting doesn't really matter. As far as I know, the storage of the country and region was dropped in the Switch games, meaning it wouldn't matter either on the long run, so feel free to keep it as-is or edit it if it worries you.

49 minutes ago, Cursed Wizard said:

I don't plan on bringing mew to tournaments other than using it online for some friendly matches. Would I be banned if I do?

Not aware of any ban possible in your case since from what you're telling, the Pokémon would be identical to one that could have been received back in the days = legal Pokémon.