SUCCESS!
It was a LONG road but I finally got to the end and got the darn thing registered. Here is what I did:
1. Create another Amazon account. As I said previously I tried this before but I wondered if doing so from the website might be different considering so many other aspects of Amazon doesn't make sense (things should work when they don't etc). I did and if you create an account from the website it does NOT require a mobile phone number. Odd if you do it from a kindle it requires a mobile number.
2. I entered the email and password into the kindle and I got a "Authorization not complete, check your email." I thought this was odd considering I did a reboot/reset and usually after that I get the "Can't find that account" message (which would send the OTP). But when I got the "Authorization not complete, check your email" message I never got a email. So I reset/reboot it again and tried a second time, with the same result. But then on a hunch I checked my email and sure enough BOTH OTP codes were there.
3. Entered the email and the OTP code from email and it registered! Blink and done, it was so easy I kept watching, waiting for the other shoe to drop.
4. Went over to
https://www.amazon.com/myh/household...d?tag=mr060-20 to link the accounts and all is good now.
WHEW. But it goes to show Amazon does have some large bugs in their system that come up with some accounts. In my case it gave me a "unable to find account" yet would send a OTP, but it didn't work. But if I got a "Registration not complete, check your email" message on the kindle, it NEVER SENT the email. And of course they don't have a mobile phone number for me, others don't either and it still worked fine. It worked for this new account without an issue. If one has a mobile phone number and are willing to give it to amazon who will hold it in a death-grip, that might work as well but I was unwilling to go that route.