It is indeed clear that this is far from clear! It is indeed perfectly possible that the writers themselves do not really know how it is supposed to work. I just try to construct an interpretation that makes at least tiny bit of sense to me.Well, I agree that this could be argued many different ways. It's far from clear to me. Maybe that was the writers' intentions - to have people arguing about it. The whole gruesome mess makes no real sense to me either way, whether I use your interpretation or mine.
Real Tyler, or a copy of real Tyler, or perhaps just Voq becoming Tyler like a caterpillar becomes a moth.L'Rell saying "we reconstructed his consciousness" suggests to me that a real Tyler is in there with Voq, either the original transferred in, or a duplicate of the original that has Tyler's personality and memories. To me, my consciousness is "me." Even if it is a duplicate or a clone, it doesn't make this Tyler any less "real." He would still not be Voq or an altered personality of Voq.
To me, it doesn't make sense for her to say "we grafted Voq's psyche into Tyler's" if there is not both a Voq psyche and a Tyler psyche in the mix. Instead, it should be something like "we grafted Tyler's memories into Voq's psyche."
There are obviously different personas, it is not just memories. But I still think it is ultimately one person. Like I said before, sometimes you might dream you're someone else. You don't remember the awake you, it really feels you're the person you dream being. Yet it still is you having that experience. So in a sense Voq is 'having a dream' of being Ash Tyler. But there still is just one person having that experience. This is basically what happens in split personality disorder.
If they had wanted to just craft Voq's psyche into Tyler's brain, then they could have just done that, and the whole insane plastic surgery to make Voq look like Tyler would have been unnecessary. Only way this makes any sense is if L'rell cannot really transfer souls, and he wanted to keep Voq alive and to do that she had to use his brain and body.Whether or not the physical brain is Voq or Tyler is not something I have a strong opinion about either way, though I lean toward it being at least a clone of Tyler's.
As far as being undetectable, it makes more sense if it's Voq's psyche deposited into a human brain. I don't think L'Rell would care that much whether the physical brain was Voq's as long as the essence that made him himself was contained there. She sure had no compunctions about torturing him, cutting up his bones, excising all or parts of his organs, and destroying his face forever. I should think losing the face would be much harder than losing the physical brain. After all, this is Trek. His essence can be transferred into a metal ball, and he's still Voq. She said he would have to give up "everything" and that might have included his physical brain. As I said before it makes no sense at all that they even kept his Klingon bones and muscles, unless maybe they were supposed to be much stronger and therefore more useful in completing his mission.
I think the drama is about person struggling with who they are. It is 'two people trapped in one head' in poetic sense, not in literal. Real life split personality disorder has been described with such terms often enough. I think that the memories bleeding over and Tyvoq being confused about things and eventually descending into madness supports the idea that there is really just one person having that experience. It is not always clear either or, the two personas can mix.It seems to me the whole drama and poignancy is in the fact that two enemies are trapped in one head, struggling for primacy. The writers even have Saru state as much outright. If there is just one being in there all along, with some stolen memories, it loses practically all of its dramatic punch for me.
Presumably they needed him to register as human in medical scans, so he has to have some human DNA implanted.You've given me food for thought though. What do you believe the harvested DNA was used for?