Unless there's some WoJ on it that I haven't seen (and there's a lot of WoJ I haven't seen, I avoided all of them for a long time, so it's a distinct possiblity), there's not much to go on from a Doylist perspective.
Depends on how you define finding Doyalism perspectives. Jim has poured himself into his work as all writers, and has done numerous interviews about his work.(in which, he has discussed magic and world mechanics extensively) If you look at these things akin to a profiler looking at a crime scene or left messages then, there's alot to consider along the general lines of "why would they have this happen, what rules, tropes, or ideas did he use?". These are the things I try to consider with my own theorizing that usually make them seem so crazy from the other side lol. I'm pretty sure some things I've guessed with this have come to pass now, but I don't remember what offhand. Waiting/hoping on more, just cause they're really good plot hooks if I'm seeing them right.
It seems to me like they can all be possibilities from that point, but for them to be truths in branch realities, and foreshadowing for those branches, it'd require that there be catalysts for branches. I tend to think branches are rare, but that's based on personal preference rather than evidence. I don't like the infinite-splinterverse concept.
Fair enough, I actually enjoy multiversal stories, for various reasons good enough stories don't always have to make sense(all you zombies), though I prefer ones with definite rules. I think they're pretty basic in the DF, and the most defined evidence of them in action is those characters who have some talent in foresight. The alshavara cabbage patch doll thing, Steed, that one Ordo member. Now, whether those things are happening in tandom or are only possible flow of one single river of time is debatable I suppose. Could be that it's back to the future 2 like and the only thing we actually experience are the snippets of previous time travelers actions in changing the timeline.
As far as what I think we're seeing, is clue bat peeks into other timelines to be showcased later for either the MM or TT books. Iirc they put one clue for Molly being winter lady in the artwork, why not more? Jim likes his games, puns, and long con jokes, he uses imagery from things he's seen in pop culture and reimagines it for his own works, he keeps to his rules but doesn't adequately explain them in verse and uses Harry's own ignorance as the reasoning, he explains things in layers operating on an almost thaumaturgical scale for magic and how certain plot devices work. I always consider these points and more when I can