Hey Kim!
Cute shot of the puppy! Its hard to resist cool puppy shots! And I hear ya knockin’ on the “puppy only once” so get ‘em while the getting’s good!
What you are asking is very doable. I wouldn’t go about it with an eye toward white balance though. Especially if you are happy with the global WB. It would look a bit off having differing WB's in the shot.
The following example is just a Theory and a very quickie (and a bit sloppy) at that. Add H/S layer. Bring down the blues and cyans to suit. Mask and brush that in. Burn according to where you like her paws and anything else that warrants. You keep the global WB. You lose the blue on the hair/fur/coif/do. You burn back in to suit the loss of color and she's back in black!
I use one of these wading pools in my studio “wet” work along with the BRT when I hose the place. There are available white, as well as gray, as well as black small tarps that will cover the pool and give you a more controllable color-neutral starting point. You get reflector (white) flag (black) close to neutral (gray). When it is critical for lighting, as in your case, I use these in the pool. But what you have is such an easy fix I’d just let Miss Raven romp, forget the tarps, and let Mommy fix her up in post!
But what I wouldn’t do under any circumstances is miss a shot worrying about it!
