I have heard the fan theory that the three [2nd gen legendary dogs](https://bulbapedia.bulbagarden.net/wiki/Legendary_beasts) (Entei, Raikou and Suicune) are reincarnated from the three original eeveelutions ([Vaporeon](https://bulbapedia.bulbagarden.net/wiki/Vaporeon_(Pok%C3%A9mon)), [Jolteon](https://bulbapedia.bulbagarden.net/wiki/Jolteon_(Pok%C3%A9mon)) and [Flareon](https://bulbapedia.bulbagarden.net/wiki/Flareon_(Pok%C3%A9mon))) after the tower burned down.

There are the obvious similarities, such as colour and type. But that doesn't seem like enough evidence. After all, if that were all there was, then it would be just as easy to claim that Entei was reincarnated from a Growlithe (and I'm not saying it is). Is there any more evidence to support this theory?