About the language, definitly no.
If the distribution device only distributes French WC, it would simply not allow you to download it on English game.
Now the question is: Did Nintendo make a different distribution device in each language for Europe or or was it the same device for everything.
About the green guy. Indeed it's 4th Gen, not 3rd. On that point i'm going to investigate.
Legit or not, the item will definitly work. What makes event item work is simply get it from mystery gift.
When item doesn't work, it's because it's from code putting it directly in inventory or in a shop. That rule is the same for any generation since Mystery Gift was launched.