Am I the only one who doesn’t fully understand the Keaton thing? I would go so far as to say that its an exclusive Japanese thing, that leaked over to the US.
I always assumed it had something to do with the striking resemblance to Pikachu.
Keaton’s a Kitsune, a fox.
Beyond that, I’m not sure what you’re asking.
In OoT i always assumed it was to represent a ‘fad’. Many characters mention that keaton merchandise is all the rage in Hyrule. Because the gaurd asks for a keaton mask for his kid, i also suspect a slight reference to pokemon.
I presume you are not speaking of Buster, Diane or Michael?
No, Family Ties Alumn need not apply, yet that is all that Google would show when I searched. This is from a Video Game, and is (I assume) very japanese influenced.
Was pokemon popular in Japan at the time the game was made? It came out in the U.S. in '98, but perhaps earlier in Japan? When was pokemon popular in Japan?
Given that it was made in Japan and then translated into English you could say there was a bit of an influence! 
Pokemon was released in '96 in Japan and apparently still at the height of it’s popularity by the time it reached America in '98.