1. I dunno, supernatural is an ambiguous term. The internet is a weird place.
2. I dunno, but its not IMPossible either, I've just never experienced it. Have you?
3. I hope you realize this question involving the idea of a second brain sounds ridiculous, and perhaps we could all and should learn more about it before making such bold claims.
4. Some do, some don't. Also, most of the terms in this short question are highly ambiguous.
5. How is anything possible? I don't know, but I can say from personal experience that time can be perceived many ways. Whether awake OR dreaming, our perception of time can be easily altered. They say time is an illusion because, truly, our perception of it is the only way it exists. And also because our perception of it isn't always perfect. The truth is that the confusion CAN happen, in both waking life AND dream scenarios. A person's control of it though, seems less likely imho. I think it more likely that instead it is merely our perception of it that is altered, not the facts themselves.
6. People believe all sorts of things. Beliefs are like opinions in that they can both mistaken for fact. It varies, maybe they are, maybe they aren't. I can believe the world will end in 4028, but good luck invalidating it factually until then.
And lastly,
7. People believe all sorts of things. Sometimes they believe so much that they over time become unable to see clearly the world around them...which (surprise!) is full of people who believe just as strongly, yet differently than they do. This bias is potentially present in others AS WELL as ourselves, make no mistake
Expecting to always agree on un(dis)provable things...if any thing THAT seems far more absurd.