Well, I've only ever actually created pokemon, nothing else. The only reason I fill in every field that needs to be filled in (an example not being needed is Language of the name or say you create a Scizor, then you don't need to fill in the section about which form of deoxys you want) is to make the pokemon look as legitimate as possible so that if somebody asks to see my pokemon they aren't obvious fakes but as far as I know, you don't need to edit all fields.