@Dunston While we wait for an answer, my 2 cents is that when you apply for the waiver, you should ALWAYS try and include that fact that "you might apply for a TN visa in the future" because you might get a 5 year waiver.
Most of the clients I have in this category were not criminal record related, and some were actually waiver clients BECAUSE they had TN visas and made the mistake of not re-applying for a NEW visa when they switched employers.