You are thinking from an "It has already happened"-perspective, and you are trying to justify it by looking at evidence that would help make it fit in the game as it is. I, however, am trying to look at the layer underneath. Why is it that Grimsley, someone that deals with the Dark-type and is an Elite Four member in another region, gives you a very Alolan mechanic that you need to proceed with the game? Why not someone random, like a very generic fisherman or something like that. What is the significance of placing Grimsley there?
@[member="MarineAurora"] I know where you are going. I'm just trying to find potential reasons that have evidence there. Also in that perspective, even Elite 4 members need a vacation. Alola is basically the human world Hawaii which is where people go on vacation sometimes.
Maybe there was a recurring Joke in the company that they added him. He looks like he went "down hill". So maybe making him worse then better in the games gives the game humor? I mean appearance wise guys lol