So Gorbag, who serves in Minas Morgal, and Shagrat, who serves in Cirith Ungol, (in other words orcs from two different commands), they speak to each other in Black Speech that the Ring must translate for Sam. However, Shagrat and his underling Snaga, both of whom have apparently served together in the service of Cirith Ungol for some time, they conveniently speak Westron to each other so that Sam can understand them, as do all other orcs in Mordor. Yes, I see. There is nothing convoluted about your explanations at all. It is just that there appears to be a different explanation for each occurrence.
The phrase "rebel Uruk-hai" does not "unambiguously" refer to Mordor orcs. Taken in context it is clear that the tracker orc is saying the higher-ups haven't a clue what is going on or what they are looking for. There is no "great Elf" runnning around Mordor. There is no "dwarf-man" running around Mordor. In fact, in the context of Middle Earth, what is a dwarf-man? In Middle Earth, Dwarves and Men are seperate races and no where (at least that I can recall) is there a mention of hybrids between men and dwarves. But I suppose this is another special case of Tolkien the translator putting things in words we the reader would understand, but when he uses Uruk-hai in the same sentence, a word that he has exclusively used in the book until this point in reference to Saruman's troops, Tolkien has stopped being a translator. For that matter I take it that Tolkien the story-teller has decided that despite the fact that until this point in the trilogy he has used Uruk-hai for Saruman's orcs and Uruks for Mordor orcs he is now going to take this opportunity to throw a hint to his readers that they have misunderstood his usage all along. No, the reader should cease reading the story at this point and jump ahead to read all the fine print in Appendices A and F to discover that the reader has misunderstood all along. And oh, by the way, Snaga back at Cirith Ungol wasn't really named Snaga. Snaga means slave. Thus when Tolkien wrote: "Shagrat hunted Snaga round the roof ...." we should have been reading: "Shagrat hunted slave round the roof ...". Instead of: "He cared no longer for Shagrat or Snaga or any other orc that was ever spawned.", we should have read: "He cared no longer for Shagrat or slave or any other orc that was ever spawned." Likewise instead of: "Snaga thrust the ladder upwards ... ", we should have read: "Slave thrust the ladder upwards .... ". Yes, I see now how all of this makes much more sense than accepting Tolkien's words as written. Silly of me to ever have thought that Tar-Elenion's explanations were just a tad convoluted.
What Christopher Tolkien wrote was: "In the event there was no index to The Lord of the Rings until the second edition of 1966, but my father's original rough draft has been preserved. From it I derived the plan of my index to The Silmarillion, with translations of names and brief explanatory statements, and also, both there and in the idex to this book, some of the translations and the wording of some of the 'definitions'." [emphasis added] No where does CT say that the other defintions came from elsewhere in his father's writings. That is your contention. I point out again that the book Unfinished Tales is copyrighted to the Tolkien estate, except for the Introduction, Commentary, Index and Maps, which are copyrighted to CT. The Index is CT's, not his father's.
In your zeal to claim equivalent weight for Tolkien's posthumously published work you continually overlook his son's own warnings and caveats about the books CT has produced. The first paragraph of CT's Introduction to Unfinished Tales reads: "The problems that confront one given responsibility for the writings of a dead author are hard to resolve. Some persons in this position may elect to make no material whatsoever available for publication, save perhaps for work that was in a virtually finished state at the time of the author's death. In the case of the unpublished writings of J. R. R. Tolkien this might seem at first sight the proper course; since he himself, peculiarly critical and exacting of his own work, would not have dreamt of allowing even the more completed narratives in this book to appear without much further refinement." [emphasis added] Further on in his Introduction, CT says, in regard to his father's manuscripts: "When the author has ceased to publish his works himself, after subjecting them to his own detailed criticism and comparison, the further knowledge of Middle-earth to be found in his unpublished writings will often conflict with what is already 'known'; and new elements set into the existing edifice will in such cases tend to contribute less to the history of the invented world itself than to the history of its invention." [emphasis added] These two quotes exactly summarize the reasons Aragil and I have repeatedly given as to why Tolkien's posthumously published works are secondary sources and cannot be given equal weight with material JRRT published himself during his lifetime. I expect that you will point out the following sentence by CT that follows the above quotation in the same paragraph: "I have made no alterations for the sake of consistency with published works, but rather drawn attention throughout to conflicts and variations." and argue that CT does not point out any conflict between the Fords of Isen manuscript and LOTR. The fallacy in that argument, however, is that CT's definition of Uruks being an Anglicization of Uruk-hai has defined the conflict out of existence, thus there is nothing for CT to draw attention to, at least in his mind. Without the definition, which is the very thing under discussion here, there would be a difference between the two texts.
As to CT's use of Foster's work we have the following statement in the CT's Introduction to Unfinished Tales: "I have, however, included short defining statements with almost all the primary entries in the Index, in the hope of saving the reader from constant reference elsewhere. If I have been inadequate in explanation or unintentionally obscure, Mr. Robert Foster's Complete Guide to Middle-earth supplies, as I have found through frequent use, an admirable work of reference." Note, CT does not say that his "short defining statements" all come from his father's writing. CT does explicitly state that he used Foster's work frequently. I repeat, I doubt it was merely as a paperweight.