But neither is there any solid evidence that Ruth is pre-Hartnell, is what I'm saying. For all we know she could still be from the future, or from a parallel universe, or any other things. Yes, Chibnall ruled out a parallel universe in interviews, but interviews are not valid sources.
Similarly, all we know about The Doctor (The Brain of Morbius) is that they were Doctors before Hartnell. The Thirteenth Doctor called up their images to mind while blowing up the Matrix, but that's hardly evidence that they're part of the Timeless Child story. Since there are accounts where the Second Doctor knows full well about the lives he had before being the First Doctor, it is for example perfectly possible that after the Timeless Child's memories were erased, their first life as the Doctor was not Hartnell, but rather the first of the Morbius Doctors. Who knows? And the connection with The Other is simply this: one account says the Doctor had lives before Hartnell (the Morbius Docs). Another account, which coincidentally reminds the veiwer of the existence of the Morbius Docs but doesn't discuss them as such, has one scenario of the Hartnell Doc being a preexisting Time Lords with their memory erased (namely the Timeless Child). But another, conflicting account has a completely different version of the "Hartnell Doctor was an amnesiac reincarnation of a preexisting Time Lord" shtick (namely the Other). Both of these later accounts, plus the one where the Morbius Doctors are just the Doctor with no amnesia involved, are equally valid in relation to The Brain of Morbius.
…Oh, and since we do have Template:Doctors, I fail to see the point in having a tiny category for just the thirteen "main" incarnations of the Doctor. What use would that serve? Who'd want to visit such a page when the template already gives them all the links they need? I can see value in splitting "regenerations, unplaced or otherwise" from "clones and Watchers and stuff". But I don't see why The Doctor (The Cabinet of Light) shouldn't sit in the same category as Sixth Doctor.