Who do we Play as in Five Nights at Freddy's 4? (Theory) 

You are right about CC hearing the call possibly after he possesses Fredbear, however I think there is a conclusion that satisfies every question. We know that CC has nightmares at some point. The height and toys of the room suggests CC. The 'these are friends' do not make sense if he is scared of them, but let's just say he doesn't trust them as much after the bite. These could be coma nightmares. Then, Mike. The room layout isn't the same as CC. The ways the animatronics attack suggests FNAF 1 trauma. And to top it all off, we have the phone call and the picture. To me this suggests that both brothers have the same recurring dream - after all, we know two spirits can if one attatches to the other, thanks to TFTP. This would also match up with other signs of CC haunting Mike, such as the 'IT'S ME' and the Fredbear footprints outside the FNAF 4 bedroom window.

@@longfishy I do believe we're meant to connect CC & Mike to these nightmares, but I think the whole "haunted dreams" angle is the wrong way to do it. The game itself never suggests anything paranormal about the nightmares whatsoever. I also disagree that CC attached himself to Mike. "IT'S ME" is more Golden Freddy's thing, and I really doubt the footprints are meant to be Fredbear's.

@@UnoriginalJokester Haunting is a thing just like remnant and agony is now thanks to the book story that confirmed how ghosts work, such as what they do upon death and how they move on. In the same story it mentions symptoms of haunting, and having dreams that are not originally your own is one of these. I understand your reluctance to believe that Mike and CC are attached together like Cassidy is to Afton, but that isn't what I mean. I simply mean CC is haunting Mike. Though if you don't think that is true then I can't force you. As for your other points, I would say hearing FNAF 1 phone audio during FNAF 4 presumably before either brothers have been inside that establishment is 'paranormal.' So you cannot really say that there aren't any supernatural elements in the nightmares. Also, I'm curious as to why you don't think the footprints are Fredbear's. This has been believed by most of the community for a while now. Why don't you think so?

@@longfishy I know haunted dreams have been established to exist. What I'm concerned about is what evidence there is to believe this is the case in FNaF 4 specifically. I'm pretty sure the Logbook confirms that FNaF 4 does happen after FNaF 1, given how Mike draws Nightmare in response to "recent dreams." So Mike would have heard that phone call by that point. The only way Fredbear could reasonably be those footprints is if Midnight Motorist is about the Afton family, which is something I have trouble believing. There isn't really any true evidence for that. I find it more likely that Midnight Motorist is instead about the family of a kidnapped child, and those footprints are William in the Springbonnie suit.

@@UnoriginalJokester ...Wow, that take on MM surprised me. It's stupidly likely that it is about the Afton family. I mean... The dude literally drives a purple car, which is the same as the car we see when Charlie dies. And it's set later that night. How can you not believe it's about Afton's family? Henry's one wouldn't make sense, and there would be literally no lore relevance if it was about anyone else. Maybe if it was about the family of Bonnie Bro? But that's a stretch, as Scott wasn't really focused on him as much that early on.