Luke wasn't one of the original 12. The book of James was written by the brother of Jesus, not one of the apostles, according to the introductory notes to the book in my Bible. Also, the author of the Gospel of Matthew was "Matthew, also called Levi" which makes me think it's a different person than the Matthew who was one of the 12.
John wrote the epistles 1, 2, 3 John and Revelation in addition to the Gospel of John. Peter wrote 2 epistles, 1 & 2 Peter.