I have been trying to be able to use Zeraora early through legitimate methods by using a mew with a quick claw in the mock battle and using transform, am I doing something wrong or does it not work?
Yes. You can transform into Zeraora or any other Pokemon with the move Transform or the ability Imposter. But, your Mew will turn back into a Mew if, the battle ends, you forfeit, or switch out.