The fact that I have the two AppleID accounts as listed above that are live and working is proof that it was possible at one time. Even though they have never been used with any AppleID or account anywhere EVER.
********* I login to the appleid website and try edit/change the email address on account #2 it absolutely refuses to accept any of those email addresses.
However, I would like to update the email address on Account #2 to the following: I actually have this currently setup this way.
It used to be that I could use a variation, or alias, of my gmail account for my second appleid. I have to have two AppleID accounts - one for New Zealand and one for USA because I spend time in both countries.