In the ritual that I didn't go into, there are references to Jesus and Pookong (Jesus being one of those pleased by the whipping). So, yeah, there's obviously a mishmash of faiths going on, such that you couldn't really call this an element of any one.

I imagine that the different cultures may have coexisted because there might simply not have been enough of them to do otherwise.

Sure, if you have a village to yourself, you might be able to make war on a neighboring village over who's got the right faith. But, if you're all just a couple hundred as it is, you need the help to survive.