You'd use KE miles to book a round trip on Emirates -- this will be expensive but UR are easy to earn and Emirates is a desirable product.

If you can get to JFK either via separate award or cash ticket, JFK-AUH/DOH-SEZ-AUH/DOH-SEZ is under 18,000 miles. This makes it 65/105/160 ANA miles for economy/biz/first. That's very competitive--especially the business class pricing. You will pay a surcharge that's probably almost as expensive as a coach ticket , but it's still a lot cheaper than business class paid tix...

Just to be clear, though, ANA awards on Qatar (via DOH) or Etihad (via AUH) must be ENTIRELY on the respective partner airline. You can't use Star Alliance to New York then hop on Etihad -- nor would you want to since that would put the mileage beyond the 18,000 mile threshold and increase the cost.

See here for ANA's partner chart and rules.

As far as HOW to book it:
ANA - you can search Etihad fairly reliably on Etihad Guest site. Look for "Guest Seat" availability. Qatar you'll have to call ANA.

KE - As far as I know ExpertFlyer is the only way to search Emirates space, but that may not be accurate. You may be able to sign up for a EK (Emirates) account and use their site?