Auspice, you’re a bit wrong on the wolf things. Wolves WERE removed in the 1800s, but they’ve been reintroduced and multiplying, breeding with the local coyote population (which we have plenty of in New England) and creating a ton of Wolf/Coyote hybrids. Which are clearly what you encounter in the game - after all, wolves are are afraid of humans, but the hybrids aren’t afraid of /anything/. Still, if we are going to replace them with anything, coyote hybrids would be the obvious choice (maybe not wolf/coyote, but dog/coyote with maybe a bit of wolf mixed in?)
I think the wolves are fine though. The cougars… not so much. (I also just really don’t like the cougars, heh)
Beyond that…
There are some plans to add in some infected animals beyond those you already encounter (The bees, wasps, ants, spiders, and mosquitos) There are also many plans to greatly improve animal behaviour. (Feel free to contribute! We’d love it if someone dove in and worked on this)
Orleks, for example, are going to be infected kitties, and are going to have some pretty complex behaviour - they will be much, much smarter than zombies (and much more dangerous).
There’s also some potential fun to be had with amphibians and reptiles. Not alligators - that isn’t appropriate for New England. But that’s fine - we have something BETTER.
Say hello to one of the most common examples of New England aquatic wildlife:

Now, imagine for a minute. Your average new england pond has at least a couple of these. They are everywhere. Now imagine them large. With mutant infection-related powers like an extendable tongue that whips out and drags you towards them.
So yeah.
I also want to add porcupines or infected versions thereof, since they are basically everywhere in New England (though most people have no idea. Living in trees, being super stealthy, they are the spiked ninjas of the animal world), and I’ve got some special plans for bats (See: Rust Eaters and Junk Gluttons) as well.