First off, Murphy would still have a sigificant role in the kids' lives, but she wouldn't be as important as she is now. Likewise, Gramma Katie would not play as important a role.

I think the changes would more come when the kids were older. There would be less friction between Mal and the rest of the family due to him being less magical than Fay. He would find a fellow non-mage in Miranda. I think Fay would be more girly due to Mira's influence, as Murphy isn't terribly girly herself and can't help Fay in that department.

I don't know if there would have been more children if Mira had lived. She comes from a big family and Harry never had one, so I think they'd both want a largeish family.

Harry would be able to work more since Mira could look after the kids, so there would be a bit more money in the house. They might have moved into a bigger place than the townhouse.

For all that, though, I'm not sure how much would change if Miranda had lived. Besides less angst, I think the uniqueness of the family would remain whether Mira was there or not. And so, the quirkiness and the sense of family would be the same. However, it would open a whole host of storytelling opportunities in terms of what it's like to be married to a wizard.

Thank you for the nice words! It's always nice to hear things like that. I was so worried about bringing in Miranda and the kids and it's wonderful to hear that people like them so much. :-)

This was going to be my question, too! :D