But surely he didn't mean that the Teleri had blue hair......
It's very interesting that in pre-LR writing, Tolkien was happy to assign 'ethnic' descriptions to the Edain and the 'swarthy' Easterlings, but not to the Elves (or Dwarves). I can't find anything in the QS/Later Annals/Lhammas writings that can be read as anything but a vaguest stretch assigning physical characteristics to Lindar/Noldor/Lembi.
There is however one passage which might I suppose be read as a "dog that didn't bark." In QS Sec 130 T describes the Houses of Men, and the Beorians "were dark or brown of hair; their eyes were grey, and their faces fair to look upon; shapely they were of form, yet hardy and long-enduring. Their height was no greater than the Elves of that day, and they were most like to the Gnomes,
for they were eager of mind, cunning-handed, swift of understanding, long in memory."
That "for" is interesting; because it
seems that the comparison to the Noldor here is based entirely on the Beorians' habits of mind, not their coloration.
PS: FWIW, in the QS text of Beren and Luthien, Celegorn expressly has golden hair, so "the fair" in his case really does mean "blonde."