Was wondering - is their anything more than anecdotal evidence for the existence and order of said "seasons"?
Yes, some variable is predictable and follow the same path, for example about spending, people spend more in Q4 and spend less in Q1, that's because "holiday season" when people want to enjoy their one-year-long work at the end of the year, and nothing more to spend at the beginning of the new year. However, not every "season" is equally reproducible.
In your case, about meme-coin season and stuff, it's different than the seasonality I've been talking about. The meme coin or altcoin season is simply jargon, the more accurate term should be a trend, in it's a short-lived one. I mean meme-coin trend only last a few weeks/months without any reproducibility, thus next year there will be no meme-coin "season" IMO.