1) Is Ditto a... failed Mew?
Mew and Ditto both weigh 8.8 lbs.
They have the same sprite color scheme, with the same shinies.
They both can learn every move, though in Ditto's case for a certain period.
They both learn Transform.
Many Ditto can be found in Cinnabar Mansion where many experiments took place between Mew and Mewtwo.