Wait! No wonder you can't follow me, 'cause I'm all over the place Sorry.
Instead of a single page check out, I placed the Email address (Guest Checkout) at the front of the check out process and separated the shipping/payment portion onto the next page. The user now has to click Next before proceeding. Until then I wasn't getting the Email address in the cart table. Now when they click next their email is captured (wrong or right). So I was over-complicating matters by trying to simply the checkout.
For our event registration system I"m working on a way we can use Elastic Email (our SMTP provider) to validate the email address before leaving the email field on that system. If I can get it to work, maybe I can employ that here as well. But 99% of our cart checkouts are initiated through the event registration anyway, but that doesn't stop them from entering the wrong email address on checkout...only using 2-step registration/activation link will do that. If I didn't get so many complaints from visitors not wanting to create an account I would have focused on the registration only angle anyway and forced validation.
As always, thank you.