Other authors followed up on PPZ. Sense and Sensibility and Sea Monsters. Mansfield Park and Mummies (which I am currently reading). Emma and the Werewolves. Each by a different author which means that I should not assume that shoddy work in one implies shoddy work in the others.
I knew the undead had invaded Austen. At some point they invaded other classic works as well, for here is The Adventures of Huckleberry Finn and Zombie Jim. The Undead World of Oz: L. Frank Baum's The Wonderful Wizard of Oz Complete with Zombies and Monsters. Robin Hood and Friar Tuck: Zombie Killers. The War of the Worlds plus Blood, Guts and Zombies.