Conceivably, oral lore could have been passed down by Aztecs and Mayans (taken as slaves by conquistadors), to their enslaved descendance. It could have then mixed with the paganism tradition of European settlers. When Simone divulges her past to Mystery Inc., her tone suggests she, Lena and her commune were outcasts for practicing paganism and praying to a heathen god. Given that they only have a few dozen members, as seen in the flashback, past members may have been executed on the charges of witchcraft, forcing them to seek sanctuary in an alligator infested bayou.
Tezcatlipoca is described as a god of jaguars, the lord of the night, beauty, conflict and sorcery. He likely did not desire sacrifices, in order to retain what little worshippers he had left. But once the majority of them were slaughtered, he answered Simone and Lena’s dark desire for revenge. But Tezcatlipoca is known to be a fickle god and cursed the women with immortality. This allowed them to remain young and beautiful but also allowed him to receive a steady supply of human sacrifices, when they drained the lifeforces of unsuspecting tourists. Moreover, he would partially remake them in his image to show their devotion to him (making them his “nagual”), hence why they transform into werecats. Given that Tezcatlipoca is a god of the night, it adds up that this ritual would take place every harvest moon, at midnight and by its very nature, would create conflict. The god could have also “spoken” to Simone and Lena, either directly after sacrificial ceremonies or in their dreams, instructing them on how to make voodoo dolls to better subdue their unknowing victims.
Simone and Lena also showed they were capable of spreading the belief of their “cat god”, as they converted Jacques, their ferryman, with the promise of immortality. This likely would have been Tezcatlipoca’s ultimate goal, as a way of acquiring more worshippers.
- That would certainly answer the question of where the religion even came from. It's odd that what appears to be a real supernatural force with real power over the human world was only being worshipped by about 6 people.
If you watch closely, you'll notice that the Confederate army zombies only ever seem to come into view when Shaggy and Scooby were involved. From their view of the ghost in the mirror, to the chase in the swamp where they helped Shaggy save Scooby from quicksand, to when they threw themselves at Lena and Simone to save Scooby and Shaggy, and even in the last time we see any of the ghosts when the lead Confederate salutes Scooby while thanking him before vanishing. If you watched Scooby-Doo Meets the Boo Brothers movie, you know that Shaggy's great or great great uncle Beauregard was a Confederate colonel. Given that any time these zombies showed up, they were trying to help or warn Shaggy and Scooby in some way, it may be that they either believed that Shaggy was his great/great great uncle, who was a colonel that they knew, or they recognized that he was a descendant of said colonel and were trying to help save him and Scooby by extension for that reason alone.
