From the previews it sounded like you meet different people in the same places depending on your psychological profile so it's likely your character is imagining them.
Could be, but I get the feeling among the many "reimaginings" this game is doing is doing away with such subtlety but we'll see.
Actually, on that subject there is one "reimagining" I'd like to see for this series, and it's something that was actually proposed by a character in Silent Hill 3: at one point in that game, your main character starts getting self-righteous with one of the more enigmatic characters in the game. In response, he suddenly starts lecturing you on hypocrasy, asking how Heather can be so self-righteous considering all the brutal things she's done to so many "people" in the game. Heather, shocked, asks him if he's talking about the monsters. He just grinningly replies..."they look like monsters to you?" Sadly, that idea gets dropped immediately after he asks it, but I always felt that was a fascinating idea for the series: that what you see as monsters in the game are actually other wanderers/lost souls just like you, and that Silent Hill alters your perception of them for its own twisted ends.
Now THAT would be an awesome idea for a Silent Hill game.