The confusion you have here is that you have the wrong conception of "identity". You are assuming there is a single "authoritative" identity established by your physical being, and that is the fundamental error here. You can't refute that by simply assuming it again.

I'm not the same person I was when I was 30 years younger, and I'm not the same person here that I am in person. Those differences are differences in Identity. It doesn't matter if you want to call the 'different facets', because the only thing that matters is that they are distinguishable, and thus not the same identities. Your understanding of Retra is as much an understanding of me as it is an understanding of 2-year-old me.