TL;DR: I think we’ll see an Evolution event tied in with Meltan and its evolution Melmetal after the Halloween event.
Two months ago there was a post from someone who predicted the gen3 Water Festival last December which actually turned out to be true. Needless to say that the same didn’t happen with the “Evolution Event” unfortunately. But I don’t think we should rule it out completely. Especially with the arrival of Meltan next month which we now know will be a quest to evolve it into Melmetal. Yeah. Meltan has an evolution.
So if I had to guess, and I’m just guessing here, this may just be Niantic’s way to have an Evolution event for gen 1-3 pokémon by introducing new pokémon and why we didn’t see dark and ghost types such as dusknoir, froslass, weavile and honchkrow make an appearance for this Halloween event. This event could very much start next Friday after the Halloween one which would pretty much be a nice transition moving forward since I don’t see them doing this in December.
November I feel is a great month where a lot could happen between now and December for dark, ghost and ice types. Those three fit perfectly between October and December. Froslass is ghost and ice, weavile dark and ice, dusknoir is pure ghost, honchkrow is a dark type. The other typings which are elementals and fairy (works with ice types and Christmas I think) are a coin toss but for the sake of the others I see this working. You be the judge here.
More wishful thinking at this point, correct me if I am wrong but togetic has never been available through anything before but as an evolution or an ultra rare spawn. It also, as you know, has an evolution in gen4 and a pokémon that will be very rare for some to obtain since togepi is a rare hatch. The togepi family until now hasn’t been available to us through raids, research or anything else and again is the only past gen pokémon needed for a possible Evolution in a month between months that celebrate global holidays Halloween and Christmas. So with that said, I’d say November is a pretty good month for all of this to take place. If I’m wrong I hope this was a fun read. GG.