Octomom aside, most of us only have the opportunity to name a small number of children. Authors, on the other hand, can name family after family–including the parents. Some–like Jane Austen–were limited by the restricted supply of names available in their milieu, while others could let their imaginations soar.
I thought it might be fun (and instructive?) to look at some of the more prominent brother and sister sets in literature for possible ideas–though you could probably skip Wallstreet Panic.
Alcott, Little Woman
Austen, Pride and Prejudice
Austen, Sense and Sensibility