well, i can answer you only to the question about the flying. YES! it really feels real! The feeling is just...i can't really explain it. you have to experience it to know what is it like. And yes i think the brain CAN gather enough info to make things feel realistic. Have you ever had dreams that you feel something. You touch something in your dreams but you can really feel it on your hands? Well, flying and all the others things u asked are pretty much the same.