First of all, the powers are based on the Gold Dragon God, it means he can turn things into silver. And the appearance of the unnamed Silver Dragon is the same from Yu-Gi-Oh.
Yes, I stopped using the template temporarily, but that's because I didn't watch the end of Fairy Tail. This is an idea for some author who likes Fairy Tail and was thinking about writing something.
I don't have any requirements. You can make the protagonist have knowledge of canon or not, be reincarnated or not, be part of the 400 Year Plan or not, I don't even care if you turn the MC into a dragon as long as he can have a human form.
I barely remember the anime and I don't know the ending, but if you want to write a fanfic, just give me a call and I'll do everything possible and impossible to help you.