Apple treats old versions of my Apple ID as if they are separate accounts?

Question

I am transferring my data from one iPhone to another via iCloud.  Overall, the transfer is going fine.
However:
A long time back when the iTunes store first launched, I created an Apple ID to purchase music.  At the time, this was just a user name.  However, my usual username was taken, so I created usualname1.
I found I had a hard time remembering to use this variation, so some years later, I changed the user name to drusualname, which was easier for me to remember as I'd just gotten my PhD and was starting to use this variant elsewhere.
Then a few years ago, Apple forced all Apple IDs to be changed to an email address.  So I changed the account name a third time, to [email protected].  So far, so good. 
(What's critical to understand is that these are not "separate accounts," which I know can't be merged, but the same account with changes to the user name.)
As I'm transferring data to my new phone today, I am being asked to enter passwords for usualname1 and drusualname.  Should be no problem, as I've had the same password the entire time, right?  Except that the iTunes store or iCloud or whatever is rejecting the passwords as incorrect.
So I go to http://appleid.apple.com/, and try to retrieve the password for both user names.  The first thing I try is "use security questions," but I get hung up in the same spot on both - it won't accept my birth date.  Now, I know my birth date hasn't changed.
So I request a password reset for each via email.  Except that it's been 10 minutes and I still haven't received either reset mail.  I've been using [email protected] for longer than I've had an Apple ID, and have never changed the email address on my Apple ID account.
To recap:  I have only ever had one Apple ID account, but the user name has changed twice.  Apple is now treating each user name as if it were a separate account, and refusing to recognize the password, my birthdate, or the email address which has been the same the entire time I've had an ID.
Help?

Answer 1

In Settings>Messages>Send & Receive on each phone, make sure the numbers and email addresses are seperate and you don't have the same address or number selected on both devices.