When somewhat younger and even more name-obsessed than now, I used to wonder if Rowan's name was a reference to her uncle Rollo (God knows I can't think of any plausible way to feminize it otherwise). Peter seems to be a two-for-the-price-of-one, since there are Peters in the Marlow family tree as well if I'm remembering correctly.
I was about to chime in on the weirdness of the way we learn about the uncles (not so much us as Nicola, I should say), and then realized that I was past thirty before I knew about an uncle who died before I was born (as a small child, admittedly). Families are strange.