In short: No.
Aldous Huxley made clear in several of his subsequent writings that he was not very interested in fleshing out the setting he had created in Brave New World. As time passed, he was much more interested in seeing how the real world had developed, contrary to his expectations; and in considering how he could have written Brave New World differently.
Much of my discussion here will be based on Huxley's comments in his collection of essays, "Brave New World Revisited," from 1958, twenty-six years after the publication of Brave New World. The purpose of the collection was to given his then-current thinking about many of the issues that he had raised in the novel. In general, the essays are quite pessimistic about the future. When he wrote the Brave New World, Huxley thought that a sea change in the nature of human culture would be required in order for the dystopia he envisioned to take hold; but by 1958, he thought that dystopia could actually be a natural outgrowth of the changes that had overtaken the world in the twentieth century. (The whole thing makes for very interesting reading. While I disagree with Huxley on many points, he clearly has put a great deal of thought into the questions at hand.)
One thing that is immediately evident from reading "Brave New World Revisited," is that Huxley was framing the essays entirely based on his personal recollection of the novel. Not only does he not always have a crystal clear idea of how things worked in the setting he had created, he does not care; in fact, he did not even bother to reread or consult Brave New World to get details of the setting accurate. In the very first essay ("Over-Population"), the author indicates that he does not remember how far in the future the novel takes place:
I forget the exact date of the events recorded in Brave New World; but it was somewhere in the sixth or seventh century A.F. (After Ford)
He later gives other details that similarly indicate he is working purely from the memory of what he had written a couple decades earlier.
In the Brave New World of my fable, the problem of human numbers in their relation to natural resources had been effectively solved. An optimum figure for world population had been calculated and numbers were maintained at this figure (a little under two billions, if I remember rightly) generation after generation.
Careful world-building was not Huxley's way. In this 1960 interview with The Paris Review, he explains that he largely makes up his plots as he goes along (including the plot of Brave New World), without mapping things out extensively in advance. Moreover, he writes and edits one full chapter at a time, minimizing the need to go back and re-analyze what is already effectively finished.
I work away a chapter at a time, finding my way as I go. I know very dimly when I start what’s going to happen. I just have a very general idea, and then the thing develops as I write. Sometimes—it’s happened to me more than once—I will write a great deal, then find it just doesn’t work, and have to throw the whole thing away. I like to have a chapter finished before I begin on the next one. But I’m never entirely certain what’s going to happen in the next chapter until I’ve worked it out. Things come to me in driblets, and when the driblets come I have to work hard to make them into something coherent.
Finally, in the foreword to his final novel Island, Aldous Huxley indicated that, since the publication of Brave New World, he had decided he should have created a different setting instead:
If I were now to rewrite the book, I would offer the Savage a third alternative. Between the Utopian and primitive horns of his dilemma would lie the possibility of sanity.... In this community economics would be decentralist and Henry-Georgian, politics Kropotkinesque and co-operative. Science and technology would be used as though, like the Sabbath, they had been made for man, not (as at present and still more so in the Brave New World) as though man were to be adapted and enslaved to them. Religion would be the conscious and intelligent pursuit of man's Final End, the unitive knowledge of immanent Tao or Logos, the transcendent Godhead or Brahman. And the prevailing philosophy of life would be a kind of Higher Utilitarianism, in which the Greatest Happiness principle would be secondary to the Final End principle -- the first question to be asked and answered in every contingency of life being:
'How will this thought or action contribute to, or interfere with, the achievement, by me and the greatest possible number of other individuals, of man's Final End?'
