It's not correct that wolves die in the movie. We see wolves eating a pup that is already dead (rather graphic scene), but no other wolves are seen dead or dying.
The cat is seen rather briefly, licking its dead owner's bloody hand, then gets startled and leaves. It's up to you to decide whether it's about to start eating its owner or not.
I woudn't say a head is squashed, but several people are shot in the head, and I think one of those who have been shot has a golf- or tennis-ball-sized part of his face missing. Not seen too close up. Another person is stabbed in the top of his head, vertically. A dead wolf pup has its head torn clean off by a grown wolf.
One or more of the many, many people who are shot in the head may have eyes missing or damaged or at least covered in blood, but I'm not sure. There are so many dead people at the same time, and there's so much blood.
A middle-aged man whose wife is pregnant (pretty far along) and the middle-aged father of a recently deceased girl are killed. Other than that, I'm not sure, since a very large number of adults are killed. Like, all over the place... so I couldn't really keep track.
Most likely not, but we never know for sure. There are a few lines here and there about demons and stuff like that, but it's vague. We don't even know if they're talking about possession or just supernatural influence.
the woman is seen muttering to herself and then has a mental meltdown, and later on turns out to be the murderer (ableist against psychotic people + stereotype of trauma survivors, in this case incest, becoming evil)
Multiple people shot in the face with bullets or arrows, blowing open their cheeks, necks, and knees. The camera does not shy away from these moments and is often the only thing to look at when on-screen with little-to-no warning of their occurrence.