Ray didn't just elect to burn himself because Isabella would panic over high-quality goods being lost. Ray is fully aware he's her biological son, and how she'll go to any length to save his life. Burning himself would make Isabella panic enough to let down her guard.
The fact that the demons that farm humans are against religious demons doesn't seem like there'd be a need for conflict between both sides just because religious, nomadic demons do not eat humans. Then it's revealed to be because eating humans grown as cattle is looked down upon by religious demons who actually eat "wild" (Humans who raised themselves). The religious ones have likely tried to break the pact between both sides in the past to hunt again, which the more pragmatic demons frown upon.
Peter Pan and the Lost Boys will never grow up and thus will always be young. The children in the farm system are supposed to die young, thus never growing up.
It is fitting that Peter Ratri is the one ensuring that the farm system continues and that the children never grow up.
The fact many of the demons actions mirror the real-life cruelties and systems involving humanity only makes sense when it is revealed they become biologically similar to humans as they consume them. They'd naturally mirror some of the worst traits of corporate greed, cruel hierarchies run by the elite/rich, gluttony, and how we treat animals for the slaughter.
The fictional Vida flower that is seen growing from the victims' chest when they are about to be harvested looks very similar to the real-life red spider lily, which is regarded in Japanese and Chinese culture as "a flower originating from Hell". Demons are often depicted as creatures originating from Hell.
