The tone of your story is something else to keep in mind with your worldbuilding. When planning a furry world, you want the details to match the tone. Watership Down is a story about society, and so there is a lot of focus on the mythology and the religion, the underpinnings of their society. Zootopia is a story about human problems but made accessible to all ages, so in addition to the structure of society set up to accommodate the people there (the districts, the special designs for the cars and homes), there are animal puns everywhere. They work with the tone of the story, but when the story gets serious, the animal puns fall away.
Another area where tone is important to consider is in what your characters eat. Because many animals (including us) eat other animals, that simple basic need becomes fraught if lots of other animals are sentient. In a world like the one in Zootopia, with that lighter tone, none of the animals eat other animals (unless they go feral, but even then there’s really no discussion of them eating fellow animals, just wounding or killing them)—they eat bug protein. This is never really brought up in the movie, but there are background ads for “Bug Burgers,” and it’s discussed in some of the supporting materials. The division between predator and prey was critical to the movie but it was never actually acted out.
In Watership Down, by contrast, the rabbits are prey, and this is important to the central plot of the book: finding a place where they can feel safe. Rabbits are lost in the story to people, to foxes, and to other rabbits—General Woundwort trying to become a predator himself is perhaps his defining character trait.
My own solution for my Forester Universe books is to draw a distinction between sentient people and domestic animals. Basically, the domestication of animals happened much as it did in our world, because I figured if wolves and bears and foxes followed the same path to civilization, it would make sense for them to domesticate some prey species for the same reasons our ancestors did. That didn’t mean all prey species; some of them also became sentient, but not the domesticated ones. So my carnivore and omnivore characters eat pork chops, and there are boar people, though not domestic pig people (and there are horses, but not horse breeds; wolves, but not dog breeds).
This brings up another aspect of furry worldbuilding: the difference in how we as the reader view things versus how the characters in the story view them. How would a wild boar sitting at dinner with his wolf friend react if the wolf ordered pork chops?
It’s shocking to us because this is the first time we’ve been introduced to this world. But you can decide what the customs are. Maybe the boars have grown up knowing there’s a distinction between them and the domestic pigs, the way we wouldn’t really be offended by people eating monkeys (or at least, we wouldn’t take it personally, though we might be offended on an environmental level). Boars are omnivores, so they might eat pork themselves. There might be religious proscriptions against it, depending on how your religions are set up. It might be considered rude to eat pork in front of a boar, or it might be considered aggressive, or it might be fine, and you don’t have to decide on just one attitude for the whole world. Different cultures and different individuals within those cultures will have different views, just as there are differences in eating and drinking customs between cultures in our world, and people who adhere more or less to those cultures.
And whatever the attitude, these people will have lived with it all their lives. Shock comes from when someone deliberately violates those norms. In our world, comparing humans to apes or monkeys is an aggressive slur; the equivalent in a furry world might be calling a boar “pork chop.” But if boars have grown up around people who ate pork and have internalized the differences, they’re not going to be shocked if someone orders a pork tenderloin meal near them.
The way people talk in a furry world is also worth considering. Do you want to, as Zootopia does, have furry puns that are more for the viewers than the characters? (“Zoogle” is funnier if you know what “Google” is, as we do but the people of Zootopia do not.) Do you want to invent a language for your people, as Watership Down does? These matters of style are up to you, but at the very least, you need to consider language in the context of the society you’ve created.
Back a couple decades, there was some debate in the furry writing community about whether the upper extremities were called “hands” or “paws” (some picked the compromise “handpaws”). Either of them works, but they produce different effects. I choose to use “paws” most of the time, to remind the reader of the furriness of the characters, but I ran into problems with deer and horses (among others), who don’t have paws. For them I use “hands,” and that’s a distinction in my world. The debate hasn’t gone on for some time, and we’ve mostly settled on “use whatever you want.” When I started reading Rukis’s books, it felt a little jarring to me that she referred to her people as “men” and “women,” something I stayed away from, but she makes it work in her stories.
When you do change words like that, you have to be careful of idioms. “Give me a hand” is a common expression, but how would it sound in a world where hands are “paws”? “Give me a paw” works, but can you similarly change “hand me that thing”? What other idioms would furries come up with? I’d advise against overwhelming your reader with furry world-specific jargon, but a few well-placed phrases here and there can really give your world a distinctive feel.
Basically, when considering diet or language, you have to consider how this society (if not necessarily its people) have evolved. What customs are in place to allow everyone to live together relatively peacefully? Ideally, your story will have something to do with these differences, though it doesn’t have to. If you are exploring these customs, and maybe where they break down or can be exploited, you are telling a story that’s interesting because it’s a furry world.