I am pretty sure they intended to imply this guy is Ash. Because this game wasn't developed by Game Freak and has a dubious place in canon, they could get away with indirectly implying it.
>first Pokemon was a Pikachu
>seen Ho-Oh twice
>daughter looks somewhat like Misty
They're very vague on when the game takes place but the region looks somewhat post-apocalyptic so it could definitely be set in the far future.