Okay so, I wouldn't use wikipedia for medical stuff, as most of it isn't written by medical professionals, especially when it comes to mental illness, and most of the info is outdated by a good few years. I personally have an anxiety disorder (GAD) which is why I wanted Daphne to - or at least hint to - have some form of abnormal anxiety.
Neuroticism is different as a personality trait than it is as an actual anxiety disorder (Much like when people say that they're "so ocd"). Medical neuroticism, is scientifically known as neurosis, which in hindsight I should've used in the first place, and from my experience generally manifests as a tendency to severely overthink things, and interpret small meaningless things as problems, as well as a tendency to obsess. In Daphne's case, it's the body language thing and her desire to work harder and to succeed above expectations. Neurosis also tends to occur with perfectionism and control freak behaviours.
So Daphne, with body language, assumes that it is common sense to interpret body language as a form of conveying information (ie. if you want someone to be quiet or go away, by changing your body language to convey this message, they should understand and follow suit) though often non-overthinkers don't pick up on the subconscious message, even though Daphne does. I have a friend who does this, all the time.
Also I can speak from experience on the dog thing. I have both a cat and a dog, and the dog just cannot pick up on emotions or understand when to leave some personal space, whereas my cat is basically furry person and completely gets it.
Hoped that clears things up.