They'd be called that person's relative.
When a person imitates another person, it is called mimicking or copying.
That is called a metonymy. It is a figure of speech where one term is substituted with another term that is closely related or associated with it.
A person who comes from another country is called an immigrant.
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.
A person from another country is typically called a foreigner or an international person.
Person under control of another is a puppet
Prejudice, discrimination, judging?
This person would be referred to as one who advocates discipline ( disciplinarian ).
A person who translates one language to another is called a translator.