I think human names for pets were uncommon in 20th-century kiddie litterature, but in my real life experience, they were common. E.g., in 1956, my mother named our first German Shepard Eric. She named her Pomeranian Misty, which can be a name for a human stripper. ;-p
My cat’s registered name is Katrina. She likes jumping up on the roof of my house, so one of her inhuman names is Roofy.
I think it would great if human parents gave their kids stereotypical pet names. Imagine the respect a name like Spot Johnson, Fido Fredericks, or Rover Reynolds would command! However, something like Roofy Trump might be a hindrance. ;-)