Well I assume with the comic that they would be purely his imagination.
Peach representing the little girl (as it was her doll) because he wants to protect her from evil, as that was the last thing he was trying to do before hitting his head (the little girl said the doll wanted to get away from the bad man; which was an obviously some kind of way for her to let something of herself get away, as just her by herself could not) which became the douche person who works in the asylum (Have you noticed how in films about prisons and asylum, there is always that one guard that actually loves to pretty much torment the patients/prisoners?)
And Luigi... Hm, this ones harder to think of an idea behind why he was there... Perhaps he's just the person who was on the phone with Mario at the start of the comic, so Mario recreated him in his mind as a companion because he essentially loves his family?