It's not like that would stop Nintendo. Japanese patent law is much less strict on the concept of prior art. IIRC, you can essentially tack new claims onto old patents and the Japanese patent office will treat the result as if the new claims had been patented by you all along. They did that against Pocketpair already.

This time they have actually announced that they started the work to get the game finished somewhere next year. And as this is such a cash-cow for them, it would be dumb of them to alienate the customers.