Interesting stuff. The re-creation of Spanish geography in place names, the ancient history of piracy around those islands, ties to the Spanish kingdom. All leads me to believe this was a secret society founded by pirates and kept going as a sort of organized crime gang surfing on their old wave of power on the island.
The occult parts are often present in secret societies for various reasons, perhaps only to cement the loyalty of members. Or in a time when science education was far from prevalent, to imbue a deep respect for the order.
Either way it sounds like the occult stuff was just a small part of their business. It was in fact just a crime syndicate that had devised a way to rule over their island.
I really want someone to find that book and carbon date it. Would not surprise me if it was from the 18th or 17th centuries.
One of the great things about reading articles like this is to open up Google Earth in another tab and follow the geography. I'm always amazed by the land of South America. From the southernmost tips to the Amazonian basin, the entire continent feels so desolate, so stark, so lonely. The geography of Chile's land below the Maule river is stunning to follow - at least on Google Earth.