Not having read the story, we can only guess. The little wife is surely a key character. There could be a neighbor who is either friendly and helps her out or is jealous of her. There might be a local shopkeeper who she interacts with regularly and through whom we learn more about the neighborhood and her place in it. And if there's a mystery or a secret in the story, there could be a character who holds the key to that mystery, like an old acquaintance from her past who shows up unexpectedly.
Often in novels with a king as a main focus, there will be antagonists as well. So in this 'the little king next door novel', there could be an evil wizard or a rival king who tries to undermine the little king. And on the positive side, there might be a wise old man or a brave knight who helps the little king. Without reading the novel, it's difficult to be certain about all the main characters, but these are some possibilities based on the genre.
I'm not sure specifically as there could be many different stories with this title. It might be about a young woman who is the neighbor and perhaps her daily life, relationships or some unique experiences she has.
Obviously, the boy next door is one of the main characters. There might also be the narrator, who could be a neighbor or someone who has a close relationship with the boy next door.
As I don't know the story, it could be the parents in the family next door, their children, or maybe even the family pet.
Since I don't know the specific story, it could be the star, who is likely a central character. And probably the neighbor who discovers or has a relationship with the star.
I don't know as the information given is too limited. But it's likely that the girl next door is a main character, and perhaps there are also her family members, friends, or neighbors.
There could be a neighbor as another main character. Maybe an older person who gives the girl advice, or a peer who becomes her friend or rival. For example, if it's a story about the girl's musical journey, the neighbor could be a retired musician who mentors her.
One possible theme could be friendship. As a neighbor, the little wife might form strong friendships with those around her.
I'm not sure as not much is given. But probably the main character is the 'devil' neighbor and perhaps some of the neighbors who were affected by this person.
There are two main characters in 'the shrink next door true story'. One is the shrink, Isaac Herschkopf, who is the central figure in this unethical scenario. The other is Marty Markowitz, the patient who becomes the victim of the shrink's inappropriate behavior.