How do you distinguish this from "If I can convince myself that the past version of said loved one would have considered this being as themselves, then I too can consider this being as them"?

You can't, but that's true by definition for any empirical question. You can only do the best you can with the information you've got.

If that fails, but the so-called "resurrected" being BELIEVES it has all your first order desires and values, and BELIEVES it retains a few key memories, but this "you" is no longer there to verify that it does not, how is that different?

I'm not sure what you mean. I'd say that most importantly from you perspective, it's different because you failed to achieve your objective of creating a future being which falls under the criteria that you defined as ialdabaoth? The fact that neither you nor the ressuructed being will be aware of the failure happening doesn't change that a failure happened.