I'm starting to think that, when talking about ontology, each of us mean different things. By ontology, I mean basically "what exists" or "what is real", in which case there really is no ontological difference between any two freely chosen religions (because on meta level, dualism and/or idealism doesn't fit the observational data).

I think this is about time I used the standard rationalist trick and asked if you could unpack the word "ontological". Maybe we are arguing about definitions and nothing else.