Question: Are both Seth Grahame-Smith and Threes Anna novelists?

Context articles: The Last American Vampire
The Hard Times of RJ Berger
Seth Grahame-Smith
Abraham Lincoln, Vampire Hunter (novel)
The Lego Batman Movie
Pride and Prejudice and Zombies
Pride and Prejudice and Zombies (film)
Threes Anna
Paul Hepker
Abraham Lincoln: Vampire Hunter

The Last American Vampire is an action horror novel by Seth Grahame-Smith and a sequel to "Abraham Lincoln, Vampire Hunter", released on January 13, 2015, through New York–based publishing company Grand Central Publishing.
The Hard Times of RJ Berger was an American television comedy series created by David Katzenberg and Seth Grahame-Smith for MTV.
 The show's central character is RJ Berger (Paul Iacono) an unpopular sophomore at the fictional Pinkerton High School in Ohio who is macrophallically-endowed.
 Berger's two best friends are Miles Jenner (Jareb Dauplaise), whose ambitions for popularity cause him to clash with
Seth Grahame-Smith (born Seth Jared Greenberg; January 4, 1976) is an American novelist, film director, film producer, and screenwriter.
 He is best known as the author of "The New York Times" best-selling novels "Pride and Prejudice and Zombies" and "Abraham Lincoln, Vampire Hunter", both of which have been adapted as feature films.
 Grahame-Smith is also the co-creator, head writer and executive producer of "The Hard Times of RJ Berger", a scripted television comedy appearing on MTV.
 In collaboration with David Katzenberg, his partner in Katzsmith Productions, Grahame-Smith is currently developing a number of projects for television and film.
Abraham Lincoln, Vampire Hunter is a biographical action horror mash-up novel by Seth Grahame-Smith, released on March 2, 2010, through New York–based publishing company Grand Central Publishing.
The Lego Batman Movie is a 2017 3D computer-animated superhero comedy film, produced by Warner Animation Group, directed by Chris McKay, and written by Seth Grahame-Smith, Chris McKenna, Erik Sommers, Jared Stern and John Whittington, and produced by Dan Lin, Roy Lee, Phil Lord and Christopher Miller.
 Based on the "Lego Batman" toy line, the film is an international co-production of the United States, Australia and Denmark, and the first spin-off installment of "The Lego Movie".
 The story focuses on the DC Comics character Batman as he attempts to overcome his greatest fear to stop the Joker's latest plan, with Will Arnett reprising his role as Batman for the film, along with Zach Galifianakis, Michael Cera, Rosario Dawson and Ralph Fiennes.
Pride and Prejudice and Zombies is a 2009 parody novel by Seth Grahame-Smith.
 It is a mashup combining Jane Austen's classic novel "Pride and Prejudice" (1813) with elements of modern zombie fiction, crediting Austen as co-author.
 It was first published in April 2009 by Quirk Books and in October 2009 a Deluxe Edition was released, containing full-color images and additional zombie scenes.
 The novel was adapted into a 2016 film starring Lily James and Sam Riley.
Pride and Prejudice and Zombies (stylised as Pride + Prejudice + Zombies) is a 2016 British-American historical comedy horror film based on Seth Grahame-Smith's 2009 novel, "Pride and Prejudice and Zombies", which parodies the 1813 novel "Pride and Prejudice" by Jane Austen.
 The film is directed by Burr Steers, who wrote the adapted screenplay, and stars Lily James, Sam Riley, Jack Huston, Bella Heathcote, Douglas Booth, Matt Smith, Charles Dance, and Lena Headey.
Threes Anna (pseudonym of Threes Schreurs, born in Vlaardingen, The Netherlands, 1959) is a novelist, theatre and film maker.
Paul Hepker (b. Harare, Zimbabwe; 17 December 1967) - South African composer, musical director, pianist, best known for composing the score (with Mark Kilian) for the film Tsotsi, which won the Academy Award for Foreign Language Film at the 78th Academy Awards in 2005.
 Hepker and Kilian also wrote the score for Rendition, the Gavin Hood film starring Jake Gyllenhaal, Reese Witherspoon and Meryl Streep amongst others.
 Hepker and Kilian also co-composed the score for "The Bird Can't Fly" by Dutch director Threes Anna.
 Hepker wrote the music for the AIDs documentary "Into the Light" which featured the voice of Kenyan artist Ayub Ogada.
Abraham Lincoln: Vampire Hunter is a 2012 American dark fantasy action horror film directed by Timur Bekmambetov, based on the 2010 mashup novel of the same name.
 The novel's author, Seth Grahame-Smith, wrote the screenplay with Simon Kinberg.
 Benjamin Walker stars as the title character with supporting roles by Dominic Cooper, Anthony Mackie, Mary Elizabeth Winstead, Rufus Sewell, and Marton Csokas.
 The real-life figure Abraham Lincoln, the 16th President of the United States (1861–1865), is portrayed in the novel and the film as having a secret identity as a vampire hunter.