Picts were a "white race", if their features were not Caucasian.
While others seem to try and broaden the various considerations involved in determining the cultural ethnicity of the Pics, you seem to persistantly boil it down to the word "race".
Funny thing about the word "race." The word race was first lended the double meaning of a contest (i.e. foot-race) and a ranking of cultures -- by the English when they described the Irish...as being lesser in the race of men.
When I was in Thailand for a semester they didn't even have a word that matched race in that context. The closest they had was a word that translated to "people of the land of..."
You cling to this one word, because REH used it. So lets talk about that:
Let discuss context. In the ancient world there were many religious and economic conflicts, but nowhere does flat-out racism appear in the modern form of skin-color and facial features.
For example, from Herodutus up to the time of Lord Byron, scholars described the land of Kush as vibrant and civil and advanced as Egypt. In fact they becam more Egyptian than Egypt in the end. They believed in a sense of Ma'at, which was not to conquer and destroy, but to live in firm understanding that anything but peaceful relation would be met with appropriate force to restore balance. They quelled Egypt then went home when they could have occupied it as conquerors. That is more Civil than we are today!
Go forward to the Imperialist Era of the late 1800s. Great Britain led the "Great Scramble" to carve up Africa, subjugating the inhabitants. Depicting the Africans as primates and savages. The greatest most pre-emiment British Egyptologist of the time, Sayce, who was well connected with the gov't and military, started to find in his studies that the Kushites and Africans as a whole were nothing but sub-human primates, a "sub-race" of savages. So they were better off being ruled by Imperialist Britain. Convenient!!!
However, near the end of his life Sayce discovers Napata (near Somalia), which has more pyramids than the Nile Valley (albeit smaller). He then concludes that the Kush must have been ruled by or had an elite caste of "white race" or Caucasian ancestry.
This concept of race and the superiority of the "white race caucasians" follows the European immigrants over to America, where they use the mind-set on the American Indians and in the south for slavery.
Only a generation or two later comes REH! He is growing up in the South. Of course he echoed what all the scholars of the past 50yrs had re-iterated from the pre-eminient scholar Sayce (who was backed by the English Crown). It was a trickle effect that leaked through the generations.
So to me...if everything points towards North/South American Indians, yet the antiquated phrase of a more racist and post-imperialistic time "white raced" appears three times. Well, I'll take that phrase in the context of the time, and take all the other info that points another direction and go that way.