That's a matter of opinion. What do you mean by 'established'? Anyone who has been writing songs for awhile can call themselves established, but I would take it to mean that they are making a living in their craft with no need for an extra day job.
Tom Russell is best known for being a singer and songwriter. He was born in Los Angeles and he is an established country music artist. He is currently touring Europe and the US.
Yes, a songwriter is the same as a composer. They are synonyms.
American Songwriter was created in 1984.
Soul of a Songwriter was created in 2005.
Kenzie - songwriter - was born in 1976.
No, it is not. The word songwriter is a noun, a person who writes songs.
The duration of Songwriter - film - is 1.57 hours.
Yes, she is a songwriter and she sings her own songs.
Songwriter's Tribute was created on 1960-11-16.
Robert Maxwell - songwriter - was born in 1921.
Phoebus - songwriter - was born on 1971-01-01.
Ron Miller - songwriter - died in 2007.