I've managed to redo the barcode with an online barcode generator that looks exactly like the original one:
https://www.barcoderobot.com/upc-a/045557873103/I know i can type lol ... but i want to keep it as true to the original box as much as possible, and i don't know what font they used for it -.-;
... as for the screenshot at the back, finding that one in HQ would be a pain and to make my own wouldn't be true to the original box. Although it would make the cover look a lot better. The border is easy to do around the screenshot (border radius i think was 40px with a border thickness of around 7px)
The game description at the back, is the text i've re-typed myself with a font that looks a lot like the font they've used for the original box (aswell as the 2 red lines of text at the front of the cover).
As for the Nintendo Seal of Quality, i can't find a higher quality image on-line. The original ones that where on this cover where even worse, so this is already an improvement.
I like your feedback by the way, it encourages me to keep going and improving!