Your title is confusing but I can help address your other questions. It is hard for the human mind to comprehend nothing, as many people assume totally blind people see darkness or black. In reality, it's really nothing. What do you see out of your elbow? That's what people with NO sight "see". Black is a color and therefore they can't see it.

Your ears don't look black to you when you try to see them, they're just not there. They're outside of your field of vision. I think a good way to comprehend total blindness is to imagine everything exists outside your field of vision.

Imagine the smell of perfume or the sound of a train whistle. You don't think of a smell or a sound being black just because you can't see them. There's nothing to see. It's not impossible to comprehend but it's kind of hard because it's unnatural to anybody who hasn't experienced it.

Yes, blind people dream. People who were born blind don't dream visually but they still dream.

In two words: Isolating and lonely.