I don't know if this is a helpful datapoint, but I used the Aeroplane Star Alliance upgrade tool to upgrade an ORD-HND flight, on ANA, from Business to First.

I had to call United to ave them switch the flight from being a United codeshare (since the return is HND-SFO-YYZ on UA/AC), to an ANA flight. Until that was done, the Aeroplane site would reject it. I also had to have 'O' availability on ANA.