You are talking about race as if 'black' or 'white' were a race. This is confusing race with skin color. I have not done this and neither should you.
"2. Gladwell's point ..is that IQ testing is far too flawed to yield meaningful results"
I completely agree with Gladwell's point. My post above is satirising this thread and the discussion therein.
There are so many breeds of dogs, you can hardly find a common thing among them. This doesn't mean dogs don't exist.
Furthermore, dog breeds are nothing like ordinary human populations. We simply don't have human populations that are subjected to the extreme selection pressures that we apply to dogs, which produce breeds with strong natural talents and lots of natural deficiencies that would kill them if they were turned loose in the wild. Chihuahuas versus Great Danes. People vary, and natural selection matters, but it's nothing like dog breeds.
Whatever you mean by that, it is pretty clear that it makes sense to talk about Caucasian race (or terriers) and use that concept, even if the manifested features vary.
Furthermore the name was created on fallacious premises to begin with. From the creator of the "Caucasian race" Johann Friedrich Blumenbach:
Caucasian variety - I have taken the name of this variety from Mount Caucasus, both because its neighborhood, and especially its southern slope, produces the most beautiful race of men, I mean the Georgian; and because all physiological reasons converge to this, that in that region, if anywhere, it seems we ought with the greatest probability to place the autochthones (birth place) of mankind.
http://www.eurekalert.org/pub_releases/1998-10/WUiS-GSRD-071...
This isn't to say that heredity plays no part, or that certain groups of people won't be more likely to have certain traits. Maybe you could say that some tribes in West Africa are such-and-such. But we can't expect our eyes to reveal genetic truths.
2) I think you're missing Gladwell's point. It is not that heredity doesn't affect the brain. It's that IQ testing is far too flawed to yield meaningful results, especially when comparing groups of people tested in different places and at different times.
In the story, they mention how properly normalized IQ tests find that Asians have a lower average IQ than whites. They speculate that Asians' success in academics is due to cultural values and individual efforts -- and if you know any super-achiever Asian students, that was in plain sight all along!