Oh. Yeah that’s kinda a valid concern lol. Hope you enjoy The Magicians!

Well… there is a completely separate show (based on different books iirc) called The Magicians which as a concept is like Narnia but darker (also a bit of Harry Potter bc there’s a magical grad school). And in The Magicians they do bring up the matter of human-animal relationships since the animals in the magical world can talk and all

So basically in The Magician’s Nephew we see the creation of Narnia and how the White Witch got there. And after creating all the animals Aslan picked out two from a handful of different species and gave them the ability to speak. He also made the small animals, like squirrels, bigger and the big animals, like elephants, smaller (but only the ones that could speak changed size). So the descendants of the speaking ones can speak and the non-speaking ones (which are literally called the dumb ones in the books) can’t speak. Some species can’t talk and aren’t intelligent, like the mice in The Lion, the Witch, and the Wardrobe. But bc the mice in that book chewed through the ropes that bound Aslan on the stone table they were eventually gifted with speech and intelligence which is why Reepicheep and his friends can talk by the time of Voyage of the Dawn Treader

If you’re talking about the wardrobe they find Narnia in, that’s not their house. The the house of the old, rich professor they are staying with in the countryside, safe from the bombings during the war. The Pevensies themselves are meant to be like middle class I think

Yeah I think based on the later books, Peter would’ve been at most like maybe early thirties but probably only late twenties by the time they leave Narnia. And Lucy would’ve been like early to mid twenties. So they were adults, but certainly not old. In fact, it’s mentioned that Susan was courted by many princes and in The Horse and His Boy (warning: it’s super fucking racist and Islamophobic) she’s genuinely considering marrying someone but it turns out he’s pretty horrible. Right after the events of The Horse and His Boy, the kids hunt the white stag, see the lamppost, dimly remember the Wardrobe and end up back in our world

As for the horses, unlike in the movies, in the books it’s said that it’s very rare for people to ride talking horses bc talking horses are free in Narnia. So in the books they would’ve been riding normal horses that they probably wouldn’t bother punishing