Interesting. Very, very interesting. I had not been expecting that we would get any Feywild content anytime soon, but this is nice to see. I would buy the hell out of a Feywild/Manual of the Planes book, so this is very much a win for me.
First impressions:
Fairy (Which they should totally rename as "Faerie"). Very standard in theme for a Feywild book. I think it's interesting that the race is Small but can squeeze through Tiny spaces, but that's likely just WotC's way of dealing with the issues of there being a Tiny race. I like that the flying speed is equal to your walking speed, which allows for some pretty cool combinations in order for this race to be the speediest flier in the game with the right items. The hovering is unique, and it makes thematic sense, but it could have unseen implications (like not letting the fairy fall unless their speed is reduced to 0). The magic is pretty standard, except for the lack of a 2nd level spell at level 5 (which was likely replaced by Fey Passage). From a balance perspective, I'm not sure how much would need to be changed, but I think this could use some minor tweaks to make it less powerful right off the bat. Perhaps they could restrict Fey Passage or hovering to once you get to level 3 or 5?
Feygoblin. Interesting. Not just interesting because they are making it 5e canon that goblinoids come from the Feywild, but also interesting that they didn't do a Goblin of the Feywild or Bugbear of the Feywild. I also kind of wish that they would have provided some minor physical changes to this race from the standard Hobgoblin, like blue hair or purple tongues, but that's not really a huge issue for me. Fey Ancestry is nice, though I'm still annoyed that the actually official fey races don't get it (centaur and satyr). Fey Gift is . . . not what I would have imagined a feyish hobgoblin getting, but that doesn't make it bad. It just doesn't seem to vibe well for me. I had always had my head-canon be that feyish goblinoids were Unseelie, and thus not as nice/helpful as the Seelie fey races, but WotC may disagree with me here. They definitely should fix the wording here to prevent infinite disadvantage on enemies with Mastermind Rogues spamming Spite, but overall this feature is interesting and flavorful. Fortune from the Many is just Saving Face, but with a better name and different recharge of the feature.
Owlkocra. I love this race. This is definitely my favorite of this UA. Who doesn't want to play a black/gray Owlfolk Gloomstalker that hunts its enemies in the night, being completely invisible except for two giant, unmoving eyes that magically glow in the dark? Or a small, cute, fluffy, tree-hugging owlfolk Druid that magically transforms into a Cave Bear to tear its enemies into pieces? Perhaps an erratic owlling wizard that hordes books like that fish from Finding Nemo hordes bubbles? Additionally, the mechanics seem spot on. I don't see anything here that seems like it would be an issue at the table (unless you're very strictly a "no-fly" table). The only think I would possibly change is the reaction to make it so you don't fall. I would change this to something simple, like either you automatically succeed (consuming your reaction), or you roll 1d2 every time you would fall, succeeding on an even number, failing on an odd, but taking no reaction. These are just suggestions, though, and the race seems fine as it is now, IMO.
Bugs'-Bunnies. This race is fine. I am not sure if/how I would implement this into my world/campaign, but it is kind of bland right now. Hopfully (no typo here), whatever book this comes out in will give them more flavor than just "Zootopia-Bunnies in D&D". Most of the mechanics seem fine, some stand out as really good and unique (Hare-Trigger and Rabbit-Hop), while others seem . . . lacking, to say the least (I'm looking at you, Lucky Footwork). Perception is . . . fine, if not incredibly boring and counterintuitive to the whole idea of races not having inherent skills presented in Tasha's. If I were to "fix" this race, I would probably make them count as Fey and Humanoid (hey, Satyrs are less goat than these are bunnies, but they count as all Fey and no Humanoid). Then, I would probably merge Hare-Trigger and Lucky Footwork into one feature that would let you add either your Proficiency Bonus or a Proficiency Die to a Dexterity Check, Attack Roll, or Saving Throw an amount of times each day equal to your proficiency bonus, or maybe just once per short rest. This would make them feel a bit more lucky and skilled, but allow them to have a bit more control over it.
Overall, I like this UA. I don't think these are as flavorful or inspiring as the gothic lineages, but that's a simple issue to fix. Sprinkle on some cool lore and flavor, fix a few mechanical quirks, and I think this UA is a done deal. The Owlfolk sticks out to me as the most solid of them, with the Fairy being in second place, but there aren't any races in this UA that I am not on board with being in a potential Feywild/Planescape book. I'll be sure to look out for the survey and give them my thoughts and ideas.