I'd just stick with the W to save your points and have the free quality W breakfast from your status, the RC you'd have zilch. You should get a harbour view upgrade at the W, not as good as the Ritz, but perfectly nice and likely you'll be able to see hong kong island. Also it doesn't sound like you'd be using the rest of the RC facilities to get value from the extra cost (eg a Michelin star restaurant for a special dinner).
Not sure about the extra child charge, I didn't think it was as common if you weren't asking for a roll away bed. I've never paid it for my kid, but she's still cot/Crib age.