It's like Anne Rice has done research but not let it effect her prejudices, especially her adoration of rich people. It also feels like there are at least three separate books here. Why is Quinn a vampire at all and why does Lestat have any part of this?

Also, Manfred brought a random new prostitute into his home where they met his children like... bi-monthly? Okay, I take it back about Anne Rice doing her research. I guess it's possible someone could do this, but it would be considered infinitely strange. He might visit brothels himself, and he'd probably set up a nice home for his mistress, and he might rotate mistresses a few times in his life. But if he brought a woman into his home and she met his children, it would be because he considered the relationship extremely serious and likely permanent. Men did marry prostitutes on occasion, but whether he planned to marry Rebecca or not, doing this with her would mean she would take the place of a wife in his home.

a girl who was afraid of her own vicious Irish father and German-Irish mother

I'm reading this as saying the parents were vicious and terrifying because they were Irish and German-Irish. Anne Rice is yucky.