I’m especially perplexed by Kwint. Three sharks, two are beasts, one is an aquatic. I believe that snakes, up until this expansion, are beasts. Correct me if I’m wrong, but I think I’ve seen a critter snake now.
A Bush Chicken, despite having feathers, is a critter. As is Lovebird Hatchling, Darkmoon Hatchling, Mulgore Hatchling and Egbert.
In addition, certain insects that can fly are sometimes considered critters, and sometimes flying pets. Grasshoppers can fly, as can some species of cockroaches (I live in Florida; you don’t want to know about the palmetto bugs), but they are critters, while bees, butterflies and moths are flying pets.
And regarding the turkey pets, I’m aware that wild turkeys are strong flyers, despite being the among the heaviest, if not the heaviest, flying birds. The domestic ones, however, seem to have lost this ability and remain in fenced in areas without escaping.
I guess generations of inbreeding produce a pretty stupid and helpless bird.
I imagine there is a hierarchy of sorts, when there are pets that share characteristics of two or more families, one family trumps the other.
Penguins have feathers, but are aquatic pets, which would suggest that aquatic trumps flying. While, as you point out, Mechanical Axebeak is a flyer, which would suggest that flying trumps mechanical. But on the other hand, Robo-chick is a mechanical, so apparently, whatever hierarchy exists, if it does exist, is not consistent.
Baby Zandalari Raptor is a beast, despite having feathers, so I guess beast trumps flying. Cogblade Raptor is a mechanical.
I suggested making a mechanical shark, so that we could have an aquatic pet with mechanical attacks. But mechanical forms of aquatics seem to be classified as mechanicals. Lifelike Toad is a mechanical pet, for instance. But mechanical forms of beast, critters, dragonkin and humanoids all seem to be mechanical pets.
I suspect if we all sat down to try to figure out the hierarchy (bearing in mind that exceptions will come up), we’d probably find that undead trumps everything. If you have a critter, beast, flying, humanoid, dragonkin or any other pet family that happens to be undead, it will be classified as undead.
That’s why I proposed the Undead Cyborg pet, so we could have an Undead with Mechanical attacks. It might make Kwint reasonably possible for Undead.