In the earthbound 64 discussion board, tomato posts how he translated some old untranslated interview with itoi, i think, and it says that pokey is in mother 3 other wise there would be no point. Also, I believe video games should have some connection. Because, simply, earthbound is good, final fantasy isnt. None, another reason why pokey is inside Mother 3. Maybe this is the final stand of Pokey, i mean he is only human.
Pokey is a fat pig who likes to be a sidekick.
So of course he'll be in Mother 3. I think Pokey very well may be the same as in Mother 2. A henchman to the hidden, evil last boss. I think you might be able to fight him once or twice throughout the game. To even further the cliches, he might be brainwashed at the end.