Yeh... the 'ave maria, ave maria' is the key there. Kinda hate the hymn, but love how it works with the lyrics:

'I saw that pregnant girl today
She didn't know that it was dead inside
Even though it was alive
Some of us are really born to die.'

And his distorted bishop/papal/primate (in all senses) set, with the apes and anti baptism. I mean the man had already literally been the violated virgin Mary in Long Hard Road Out of Hell, she had to get that way somehow.

As for the clip - it could unfortunately be almost any children's choir singing it. Hope you find the source.