All that aside, cats do use their own body language towards us quite a bit, like the head-bump, the "making biscuits" thing and the slow eye blink. But they also customize things for us as well, like I've read other researchers who say cats don't meow (in a non-growl way) with each other after they are kittens, that is reserved for talking to humans.
I remember reading that domestication tends to cause juvenile traits to carry into adulthood.
One interesting side-note is the idea that humans are also domesticated animals, and that we self-domesticated. A large part of what makes us human is that we maintain a degree of brain plasticity as we age and don't ever fully become adults. A fascinating piece of evidence for this is the way that baby chimps resemble baby humans, both in looks and behaviour.
You clearly haven't met our neighbours and their delightful King Charles Spaniels.
Huh. What's your best guess how she tells males and females (of another species: humans) apart?
There is room for the cat to be deferential to the much larger human and less so to the similar sized cat. There are also cats that don't much like visitors.
My (normal size) cat was friendly to human visitors as long as they were really big (100Kg+). It occasionally attacked other human visitors, presumably because they were easily scared. So perhaps it's just trying to assert dominance, regardless of species, but based on its estimated chance to succeed.