There is every confirmation that the Other has to do with "who the Doctor was right before he was Hartnell". The fact that the Other hasn't been (directly) referenced on-screen, again, is neither here nor there. T:NPOV. A story being more recent and more high-profile means nothing.
Heck, I don't want to press the point too much, but in-universe, we still only have the Master (the Master's) word that the Timeless Child really is the Doctor. Next to that, "the Morbius faces appear in-between the Child and the Classic Doctors in a jumbled vision the Doctor uses to break the Matrix", IMO, doesn't even register as the kind of evidence we base our coverage upon.
Heck, the order the faces appear in, in that sequence, it can't even be the real order, can it? It goes "classic Doctors in reverse, then Timeless Children, then Morbius Docs, then Ruth", which can't possibly be correct in any kind of chronological order. Some Morbius faces also show up during the Fourth Doctor's bit of the slideshow because of the Brain of Morbius association (once more showing that the Thirteenth Doctor's memory of the Morbius faces, thus far, is only based on the Mindbending Contest and she's just as much in the dark as the viewer about how it all fits).