Yes, this book is just so perfectly constructed, the plotting and the pacing and the sudden arrival of Father Christmas and everything. I can see why the slapdash worldbuilding drove Tolkien, specifically, around the bend, but it simply works perfectly for the kind of story that it is.

And yes! It feels so right that it's the love of the girls and the mice that helps to bring Aslan back. Could he have come back without it, I mean maybe (probably!), but it wouldn't be as joyful.