It's canon. The canon world has rules. You can bend the rules within good reason (like an event in Oak's life that changes his personality), but it needs to be explained. With your fic, nothing is. There's a character who's an alien, who catches rare Pokemon without explanation or reason, is chosen by rare Pokemon, stops every crime, and is champion of five regions. Oak's personality is completely changed from how we know him, and he's the strongest trainer in the world, which is another complete change because canon establishes Oak as someone who doesn't battle.
Take the time to explain things. Set up your world, don't confuse your reader.