Well, I don't really agree that Strixhaven actually fits the evidence that much (beyond owlfolk, I don't think the UA actually matches Strixhaven much).
Right now my going theory is that this UA is for a July book that combines the dragon-themed and fey-themed UA into a Volo's/Mordenkainen's style monster book. The biggest break from the norm here would be that it would contain some class options, but I find that an easy jump to make if they are on-theme.
There's definitely some sort of break of precedence brewing here, but that is a specialty of WotC lately.
To beat the dead horse, the points we have towards future D&D products right now:
UA Dragon Subclasses: a Monk who has learned mystical secrets from Dragons, and a Ranger who has a pet Drake and some Dragon themed powers. Strixhaven has Elder Dragons who run organizations of mortals to whom they have taught mystical secrets. We don't know much more than that about the Dragons in Strixhaven, but the material fits like a glove, while notably not fitting with any other Setting that I am aware of.
Four Fey Lineage options in the recent UA.
- Fairies as a specifically named "Fairy" do not have much of a history in D&D at all...but they do in Magic. We don't know what Fairies will look like in Strixhaven particularly (because they have not yet detailed the Setting much at all), with two Green Houses I reckon they will be present. Magic has recently introduced larger Fairies, that would fit the Lineage description to a T.
- "Hobgoblins of the Feywild" notably deviate entirely from the established D&D story (though I'm there for it), but Magic Goblinoids are decidedly Fey. They vary from Plane to Plane, but there is a larger Goblinoid of some sort in one of the images we have. The powers of this Lineage fit with a strain of Magic Goblin from the broader history of the game:
- Owlfolk, pretty prominently featured in Strixhaven art so far, and they do not fit anything Owl related from D&D history...but work great as Owl Aven.
- Rabbitfolk don't have any history in D&D, and not much in Magic. We don't know if any Rabbits will show up in Strixhaven, but this is a recent Magic card of some interest:
I was really not expecting anything like Strixhaven before this UA, but...these six elements all fit in Strixhaven, at least in theory, while I don't see them working in other Settings at all. I'd be shocked if they put out a Strixhaven book, but I'd be shocked at anything they do with these options, frankly.