Ghosts and shadow people are considered to be real. Shadow people are believed to be evil and aggressive in nature, although a few people consider them to be a form of guardian angel. You can get more information at the en.wikipedia.org/wiki/Shadow_people website.
Yes they are. Even our deceased in Heaven have the ability to communicate. God promised everlasting life after death, which means existence after death. Are all spirits residing in Heaven, no. Beware of the evil ones.