Hi anon I'm hugging you... Cute question
Fedya: %100 rats. In human AU he had 3 of them. He also would've LOVED pet fish. A big aquarium with lots of beuatiful fish.
Boris: A budgie!!! Or maybe two hmm...
Anıl: African grey parrot (he has one in human au also) or a curly-hair tarantula.
Erina: A rabbit, a hamster seems accurate too.
Kemal: Labrador retriever (also has one in human au).
Yelena: German shepherd!!
Gaia: 2-4 rescue cats! No fancy breeds, she would be so against breeding/breeders.
Matthias: Animals aren't safe with him as you know, he's not interested either. They're a nuisance to him.
Zümra: She's that one auntie who's a big fan of fancy cat breeds asjfjjdsjfn. A scottish fold maybe. Or a Persian cat.
Jerome: I have a lot of cat lover OCs! Jerome would sooo adopt the fluffiest the biggest cat you've ever seen. No specific breed though.