They'd be called that person's relative.
When a person imitates another person, it is called mimicking or copying.
the person is called a chaufer
A person who says one thing and does another is called 'hypocritical'.
If written by that person, it's called an autobiography. If written by another person, another author, it's called a biography.
The person who speaks for another is called a spokesperson or a representative. They convey the thoughts, beliefs, or actions of the person or group they are representing.
Prejudice, discrimination, judging?
Person under control of another is a puppet
A person who disciplines another can be called a disciplinarian or an authority figure.
He is called Mawla.
When a person is namedafter another or has the same name as another person we call him/her namesake. The origin is probably the idea of "a person named for the sake of another".
friendship
An expatriate, often referred to as an expat, is a person who moves from one country to live and work in another. This can be for various reasons such as job opportunities, lifestyle preferences, or personal relationships.