The look of the mummified corpse was based on photos of the body of John Torrington, one of the members of the lost Franklin expedition discovered in 1984.
Johann August Miertsching was a real missionary who traveled on the HMS Investigator and kept a diary of their search for Franklin's doomed ships.
The music playing in the car as Rex and Lovey pull up to the compound is the theme from the film Cult Hero (2022), directed by Jesse Thomas Cook and starring Ry Barrett.