"This should be Eevee's evolution. If you level an Eevee long enough without changing it." I have to agree here, only thing is it would make more sense to be a friendship evolution or beauty evolution.
Pokémon evolving with their trainers. I had my own idea similar to this for Halloween someday, with a cosplay-like thing based off one of my favorite Pokémon. I had Dratini, Riolu, Dragonite, Lugia or Torchic in mind.