Unfortunately, you don't get to dismiss a possibility just because you're not sure how to quantify it.

I agree. One needs to work at quantifying it. I don't know how to do that. Any ideas?

Haven't read much theology have you? There are certainly theological schools of most religions that make versions of this claim. Hinduism, for example, claims that the inverse is the dream of the god Brahman

Sure, that's a valid example which fits pretty closely with the examples I gave. Actually, that pattern matches better, although it still requires some squinting. But yes, you are essentially correct so that's more probability mass away from Christianity.