The hardest thing will be the NH seats. No flights out of Canada. They only have a small cabin of 8. I've been able to get 1 seat ex-JFK and ex-IAD before, but both within 1 month of the flight. Seems like they may not release too many too far in advance.

However, I would suggest Asiana JFK-ICN-NRT might be easier to get and it's also wonderful (in some ways 'warmer' than ANA's service, but seats slightly less good)