As of the current version (0.13.1) I've found that Mobi might be somewhat too strong. From my playing around, they (unsure of gender?) definitely seemed like one of the most consistent preds for getting huge amounts of points, since Capacity tends to be a more limiting factor than how fast you can digest.
This may partially be because of the foxgirl event making Mufi and Pemma appear quite a lot, helping them snowball very quickly, especially when chosen as the Favorite Pred, since being a 3-cost makes them come out extremely early most of the time. I would make the current stats the stats if favorited, and either make the base digestion 1 less (means they can't OHKO any prey without other buffs), or cost 1 to limit them slightly.
In general, I felt redrawing a hand was a little weaker than it should be in Campaign, since decks tend to be fairly lean and easily made anyway. Not sure how to fix this, perhaps starting the deck with a bit more fluff to make it a more consistently useful option to have.
Ayla also felt kinda weak when I tried to use her - 1 point per prey per turn is glacially slow compared to more powerful options that can get buffs from Mufi and Sachiho, or their own effects like Mobi, Mobi Cat, and Nexxi, who I feel tend to be better build-arounds. I might make her 2 points per prey, or increase her base capacity or digestion some. As it is, she feels best as a 1 or 2 of to throw disruptive prey like Princess into, which I feel should be the role of characters like Darya, Queen Dayla, or Catie, who end up being able to deal with more Prey like Squirrel, Lienne, or Cowgirl better.
Darya also felt a little weak, but mostly because of her difficulty getting buffs from prey - I think increasing her base stats by 1 each or something may help her, letting her digest a few prey 1 turn faster, while still requiring support to OHKO anything (besides the goblin, but I think that's okay.)
Catie I also feels like has a bit more digestion than I would expect for a 1 cost, but at the same time, her Capacity is so small at first it might be okay. I'm not sure. I haven't gotten her in a run, so most of my experience with her is endless which is...less indicative, I feel.
Game is really fun regardless of my nitpicks so far. I end up playing it just for fun now and then, so you've got something good on your hands. Excited for more updates =)