Well, it could mean that someone is being wrongly identified as another person. Maybe in a situation where there are assumptions made about their identity, but they are not that person at all.
Most likely not. Many works with titles like that are imaginative creations rather than based on real events. They might draw inspiration from various sources but not be strictly true.
I don't think it is. Usually, titles like this are part of fictional stories. But sometimes, they might incorporate some real-life elements and blend them with fiction to make the story more engaging.