You won't be able to book EI, even as a UA codeshare, on ANA as they are not a partner. Best is to build 1-ways awards verifying each segment in incognito browsers and then call NH and feed the reps the routing you want by flight numbers but have them verify the route as you build. The staff was very good to me when I did my Asia award. They even had some recommendations that I did not see during my searches.