Fine Lore and B4. But as we see...B4 is in the process of ‘becoming’ data after being given all his memories etc. Which means your Tuvix thing still doesn’t work.
Works perfectly, actually. I'm just glad you've gone from claiming not to understand it to acknowledging that you merely reject it.
The concept of personhood and memory is well-covered in Trek. Ira Graves, the Dax murder trial, Data's resistance to being backed up by Maddox . . . all of these things suggest that, regarding B-4, Data is probably properly thought dead. Data was copying over memories and such, much as he had colonist information given to him and even Lal's memories and programming, but seemed keen on B-4's *self-actualization*, not just making a copy of himself.
Even if the child-like B-4 personality was totally subsumed by Data's data, we have it on good authority that B-4 is not the same person as Data just because he has the memories of Data.
Swinging around to Star Trek's identity, addition of the morass of Trek literature, even given the rosy picture you paint of it, is much more than merely adding memories to a character. Like Tuvix, it is a change to the very DNA and personality, as well.
The Scotty on screen is the same Scotty that has the experiences in each of these other continuities. Because he is the basic Scott.
Your argument's issue is that you assume what you seek to prove. When the books and comics weren't considered canon, it was fundamentally incorrect to claim that it was the same Scotty. The facts of the non-canon cannot reasonably be applied to the canon any more than we can describe Ambassador Worf's dining room based on Regent Worf's Imperial accommodations.
Spin Off canon is not a totally separate entity to screen canon, especially not that which predates it, because that’s its base.
It was never a two-way street. Spin-off works that aren't canon receive knowledge of the canon universe from the canon itself, regurgitating and adding to it, and often misremembering or misunderstanding it. When they have a continuity all their own they inevitably become a separate and self-referential entity, distinct from the canon version.
Canon can elevate non-canon via borrowing (e.g. Lucas and the name Coruscant for the Imperial city-planet, elements of Vulcan from TAS, et cetera), but the non-canon doesn't mean squat otherwise.
It may have all smeared together in one's head-canon, but that's entirely different.