Yes I think they are linked - I believe in this very strongly.
I think that when a person moves and talks you can see in their expression, their hand gestures, their body language, their eyes, their facial expression so many things about them.
Its harder to judge by choice of clothes, though its still a factor, because not everyone has the money or is allowed to choose their own clothes (uniforms and such) but if everyone in the world designed/chose and wore their perfect outfit I think you could learn something from their character then.
I think this goes to some extend for hair styles and make up too - some people didnt choose their hairstyles etc, so we cant rely on it as a fair way or judging, but those who did are expressing their character in some ways through their preferences.
I dont know if voice counts, but that also can tell you a lot about a person. Softly spoken people give the impression of being gentle or shy - this might be a false impression, but we cant be sure about ANYTHING about anyone else really, anything they tell us about themselves could be a lie, so we can accept it at face value if we want and make deductions. People put on different voices in different situations as well, which can indicate how they are feeling about the situation/person and the expectations placed upon them there.
My parent generation says that shoes and wether your clothes are ironed and such tells you about a person. I suppose it does, but its very open to interpretation...in one person wrinkled clothes might mean they are a slob, in another, that they are too busy having a wonderful active life to iron, in another that they just dont care about superficial appearance, in another that they werent bought up to know different, in another that they actually prefer the wrinkles. Its so vauge, its hard to tell, same with things like clean shoes.
so..um...conclusion is you can learn some stuff, but its very open to interpretation so could be misconstrued.