Hmm. I wonder if the man in the white top hat is the dream traveler?

Another possibility is dissociation--the possibility that you actually know these people, all of them, including the top hat guy, but have blanked that out somehow.

It's almost easier (OK, it's a lot easier) to just believe it's some kind of dream travel or dream intrusion.

I believe that people can enter other people's dreams, but we live in one of the rare cultures where this is considered impossible. Most cultures take it for granted that some people can enter the dreams of others. That's what shamans do, but there are bad shamans, like, witchcraft shamans. They do exist. The white top hat guy could be stealing energy by generating fear. He could be a 'psychic vampire' type. If so the key would be to train yourself not to feel emotion during these dreams and incidents--finding a way to mock or laugh at them is one good way, but I'm not saying it's easy.

Also if it was me I'd ask the guy who sent you the text a LOT more questions. He initiated contact, so I'd ask him why, WTF, etc.

Weird.