Though after I saw those files, Terez and me argued quite a bit about when they were from (and it's very much open for debate, as many RJ files were partially updated only, retaining bits of outdated stuff). She tended to think it that the "plan" for Taim to be Demandred rather than being his pawn survived for some time beyond LOC before RJ finally changed his mind. I disagreed with her on that.
I do think it unlikely that the idea survived much past the LOC book tour, maybe past ACOS, TPOD at the latest. By WH he had made up his mind, and purposefully laid clues in the book that Demandred was not Taim. But even still, RJ never explicitly denied that Taim was Demandred until the COT tour. At least, that's what appears to be the case. We don't have many reports from the WH tour; I think it was short, and then he went to the Netherlands where he was very dodgy on the subject.
That's a long time for him to be unwilling to put Taimandred to rest. And I find it incredibly difficult to believe that he changed his mind at the last minute before publishing LOC, because Taimandred was essentially the essence of LOC, from the very first POV in the prologue to the last in the epilogue.
Clearly, at the very least he had written Dumai's Wells with Taimandred in mind, as his notes on that subject are past tense. (And lost in the drama of Taimandred is the quite logical reason RJ gives for why Taimandred decided to show up and save Rand after all.)
Taimandred is baked into LOC in a way that RJ could have fixed without too much trouble—we're mostly talking about a handful of too-explicit one-liners, after all—if he'd really changed his mind before turning in the book. He also denied that he ever intended Taimandred to be a red herring, and that much at least is true!
The most compelling evidence you can offer that he changed his mind while writing LOC is that Demandred appears to have not killed Asmodean in the prologue, but the arguments against that are old, well-known, and still feasible.
It's also not difficult to believe that Osan'gar was ordered to complement Demandred at the Black Tower, since Aran'gar was ordered to complement Mesaana by joining the rebels. Osan'gar's main purpose at the Black Tower might have originally been to coordinate the turning circles with the Shadowspawn, since Shadowspawn were his specialty. The White Tower and the Black Tower were, after all, central to the Dark One's plans, the Seanchan were another huge source of channelers.
That brings me to the most important point: the foreshadowing concerning Shara was dismal, one might say non-existent, and its relevance to the story was minimal. It could have been a good place for Demandred to work if it had been made relevant to the story beginning in TSR when it was first mentioned. And maybe I'm missing something, but I saw absolutely nothing about Demandred/Shara in RJ's notes. Peter and Brandon have both publicly said that they saw notes concerning Taim becoming a Chosen named M'Hael, but these endgame notes were not available at the library.
It's certainly possible that RJ left instructions regarding Demandred and Shara, but it's also possible that he still hadn't made up his mind about what Demandred's master plan was supposed to be, since he had to ditch his original great idea. I think RJ was attached to Taimandred! Maybe he wanted Shara to come out of nowhere in the end, just to spice things up, but he should have been making notes on those plans all along, dropping small clues that would only become clear later. He did none of that.
RJ said at one point that LOC almost killed him, particularly the last-minute editing session he and Harriet did from a hotel in NYC. This is when he really started to get ill, and he'd used up all of his buffer zone that he had when he signed a 6-book, book-a-year contract. So maybe at the last minute he had a change of heart and slipped in the bit about Asmodean in some kind of irrational panic. But you'll never convince me that he did a good job removing Taimandred from the book, or even that he tried very hard. And I don't think anyone could convince me it was the right decision to make, either.
