Komala seems almost definitely LC from my perspective, giving off a sort of Slakoth vibe. I predict a physical tank with, I'm being optimistic here, 80 or so base Atk and around 55 Def. Maybe it's just because of the fact that it holds a log, which I interpret as physical prowess thanks to the whole Timburr line. Predicting decent HP, around 30 base SpD and bad Speed. Comatose looks like a good ability, as in every tier, burns make physical tanks useless. Predicting most Komala to run a SleepTalk set with Eviolite. ChestoResto and Juice with 4 attacks seem viable too.
Cutiefly and Rowlet are going to make people run rock-type coverage more often if they're viable. I predict Rowlet's HA to be Keen Eye, as there was quite a bit said about Rowlet's night vision and impressive visual skills overall, although I sincerely hope not. Big Pecks is another possibility, but it's not much better than Keen Eye. Oblivious and Cute Charm seem possible, and there's an outside chance of Aerilate.
It is said that Litten's fur bursts into flames when shed. This could be hinting at Flame Body, but that doesn't really seem to fit Litten. Litten is said to be quite smart, so maybe we can expect Anticipation? Either way, Litten's not getting saved by a hidden ability. There's an outside chance of Defiant, and I think that's our best bet for Litten.
The possibilities for Popplio. Damp would make sense. Someone before me said it will have Swift Swim, and that's most likely the case because of all the information stating that it moves incredibly fast underwater.
Rockruff better have damn good stats, because a rock type with Vital Spirit and Keen Eye isn't winning any awards for just existing.
Charjabug has the Battery ability, boosting the SpA of teammates. LC Doubles anyone?
With Stakeout and Strong Jaw, Yungoos is going to wreck face despite being a regional rodent. It is confirmed to have two stages as has been typical of regional rodents since Joey and his Rattata. I can see people Scarfing Yungoos to force switches against frail sweepers, and then hitting their pivot hard. Alternatively, an all-out-attacker set with elemental bites seems viable.
Grubbin's a Sewaddle that won't have Sticky Web. That makes it a Scatterbug.