For those who are interested:

I recently read the book "Combatting Cult Mind Control" by Steven Hassan, a professional who also helps people leave cults. His approach isn't as much of a "long game" as Ryan and Kelly's approach. One thing that Hassan explains is that MLMs are often very similar to cults, and he also explains the difference between cults and religion.

Another book to read is The Running Grave by Robert Galabraith (pen name for J.K. Rownling.) One of the detectives joins a cult to try and get someone out. The book is well researched and gives an insider's view of a cult.