Litten has literally interacted with none of the other main characters aside from Ash, and the writers clearly began developing a relationship between the two in SM7. Either Ash is catching it eventually or it'll be a Jigglypuff type of situation.
Why don't you want it to happen? Don't like Incineroar or something?
Actually its my favourite of the alola starters.
But ash already has rowlett and the writers have proved time and time again that they can't handle multiple starters on Ashs team