The last time I flew ANA was on a United code share (it was cheaper) and the check-in process was kind of a nightmare. First, from what I recall ANA does not allow you to use their online check-in if you're a code share. You can try it, maybe they've fixed this (though it was only about 2 months ago that I last flew them), but the main issue seemed to be that they do not want to allow you to select seats. They want their own customers to select seats first. This means there's no way for them to issue you a boarding pass.

This was actually on a paid ticket that I had this problem. I guess it could be better or worse using an award ticket.

Also, when I checked in at the ANA counter, their automated system couldn't find me either, even by scanning my passport. They did finally find me manually somehow, but it took a while.

ANA seems to have issues with code shares, in my experience.