I've read that others are seeing some of the same themes as I have in the initially confusing TFP episode of BBC Sherlock, but I haven't seen anyone else bring up these two particular points, so here I present for the fandom's consideration:
(*Note these fit with the idea that TFP is John's mental creation, just as TAB was Sherlock's, and that both episodes mirror each other as intentional affirmations of romantic Johnlock theory.)
1. In T6T, the crossdressing client's ex's name was Akako. If you look up Akako on baby name or name meanings websites, it is listed as a female name which translates to "red" or alternatively "red child".
In this same scene, we are shown a red balloon that represents John. John is the red child. In some form, John is Redbeard in TFP. Also in T6T, this is further foreshadowed with the added-at-last-minute scene in which Sherlock compares John to Toby, a dog Sherlock likes because of its resemblance to his memory of Redbeard the dog.
Plus, we have references further back equating John to Sherlock's dog. I don't have access to previous series to quote verbatim from, but I believe CAM was the last one to say something along these lines, at least once if not twice, in S3E3.
2. Plenty of us noticed the red letters in the credits after TFP, spelling out "ANEMOI". Someone on Tumblr brought up a great point about Jung's Anima and Animus, but I thought it was odd that the credits highlighted an E instead of another I for a closer spelling like "Animoi". Because I like word games, the first thing I did (after much back-and-forth between IMDB's production crew list and the episode screen to decipher all that ultra-tiny, grainy print so I was sure of the names and letters I was seeing) was check out whether "ANEMOI" could form anagrams.
It can, and I found two, though one makes more sense than the other. The first is "AIM ONE" (or "ONE AIM"). Not very meaningful unless I'm missing something else. (Or... unless... the One Aim of the show is Johnlock? If so, S5 has to be where this is made explicit. The writers took this series out to show us the internal dialogue; next we need to see how this translates to actions in the "real world" in Sherlock's universe.)
The other anagram is "I AM ONE". This could be read as a clincher telling us that most of the major players in John's "Mind Bungalow" - Euros, the girl on the plane, Molly, and Redbeard/Victor - are all one; they are all mirrors or facets of John himself, as shown to him by his own unconscious. Or,in the case of 'we never left the tarmac' (ie, Sherlock still hasn't woken up), this all applies to Sherlock as well, though some mirrors - especially Redbeard and Molly - can still represent only or primarily John.
(Upon rewatching, I'm seeing more and more clues that Sherlock is still asleep. For triple whammy, watch the kids' ward scene in TLD. The glass walls have clouds on them. Two of the nurses wear scrubs with sheep and fences on them. The screen plays a video of sheep jumping a fence with clouds in the sky. All paint a picture of "counting sheep to fall asleep". This is also one of two TLD scenes in which the phrase "plain sight" is said.)
Furthermore, "I AM ONE" can indicate that this episode ends with all these confused facets of the dreamer (whether it be John or Sherlock) finally coming to peace, clarity, unity. Wholeness.
These are very small points in the scheme of things, but I was quite fired up to find I'd possibly been the first to catch these, especially as this is my first time getting to watch and decode a series of Sherlock at the same time as everyone else. (I didn't watch series 1-3 until shortly before TAB aired.) So please forgive my excitement over the little stuff. :b
I admit part of me was thinking along the same critical lines as many other viewers initially, "Who the crap thought it would be a good idea to let Joss Whedon write an episode of LOST, and why is there suddenly almost no visible Johnlock?!?" But upon subsequent viewings in a separate room from the noisy cat and other distractions (like panickily having to switch VHS tapes sooner than expected, *cough*, and needing to pour baking soda over a bright blue hairball because someone attacks his toys too viciously...), it becomes clear that the JW/SH romance is as obvious as ever.
Now I'm just reeeeally hoping Eurus' gun was truly a tranquiliser, as mentioned/shown twice in TFP, and not a real gun as the bloodlike carpeting in the therapist's house suggested.
Killing John as a parallel to how ACD tried to end his Holmesian universe I can kind of understand, and this would make the huge Reset Button Of Happily Ever After ending a bit more logical, as a way of saying, "We're killing off a vital character momentarily in a nod to canon, but starting fresh next series because we're not intending to make the same mistake as canon".
Or the thread could be picked up and given concrete closure at the outset of S5, either by John surviving a non-fatal bullet wound or, as I rather hope, by the shot turning out to be nothing more than a trank.
Yes, there remains the other possibility that we 'never left the tarmac' and we're still in Sherlock's head, but that doesn't appear to be as consistent with the storytelling style of T6T and TLD, whereas TAB and TFP make the altered format relatively obvious.
If anyone is still questioning whether this episode was queerbaiting or just a delay of full-blown Johnlock, please rewatch with the considerations above, and if you need a more explicit hint (as we all do from time to time), here it is: watch with the metaphor in mind that TFP Eurus (not necessarily T6T/TLD Eurus, just TFP,) is a representation of John and more specifically his repressed bisexual nature. Tumblr writers have expounded on this if you wish to search for it. (I'm not on that site and unsure about its link sharing etiquette, etc., so I'll let you do your own footwork there.) Likewise, as seems to have been established early on, like, in prior series, TFP (John's dreamscape) Moriarty is the personification of Sherlock's sublimated homosexual nature. Moriarty's parallel is most blatant in TAB, which is another big clue that TFP, like TAB, is not 'real' but is instead one character developing internally.
(Edit: This interpretation changes slightly if it's really Sherlock dreaming, which I'm more convinced of now.)
That's all I have time to post for right now, but I would also like to heartily thank anyone out there who has posted transSherlock theories. For the past year and a half I sort of went, 'nah, am I really seeing what I think I'm seeing? Must be wishful thinking,' but yesterday I discovered that I am far from the only one to interpret this from the BBC 'verse.
There was also a bit more in S4 that could be read as hinting at trans!Sherlock (a potential theme most prevalent in S3 especially with the deleted hospital scene), but I won't go into it here as this post is alreasy long.
Anyhoo, my good friend Tac: I don't know if you watched series four, but after that Marvel fanfic (and the Lurtz fanfic, and the wrestling fanfic) I still owe you, I might have fodder for something to soothe that itch you mentioned having for more stuff like my FtM Tony Stark fic.
TL;DR:
Just as TFP's hidden credits message says "I AM ONE," Sherlock and John have faced their demons and are ready for their warring emotions to crystallise into one steadfast truth, as are they both ready to move on past TFP's "reset button" ending and become one in the lovely gay way we've been getting hints of all along. After both characters had their assorted brushes with death, we thought that surely, now, they (the characters) must see how silly it is to keep to all this furtive subtext... Well (no pun intended), Sherlock and John coming to that realisation is precisely what we've seen play out in TAB and TFP. Internally, at least.
(Either that, or S5 will tell if I'mma have to smack a scriptwritin' *bleep* upside the head. Just my opinion: it's still - yes, I know, still - too early to call queerbaiting. We know S5 is already planned, now we just need to see it play out the way all of the previous series have set it up to do.)
*Is also ridiculously happy to have an ocassion where my Oscar Wilde cosplay icon is 100% appropriate*
Addendum...
- Going through S4 again starting from TAB, as I edited in above I'm now leaning more toward thinking all of S4 happnes in Sherlock's head. The elephant theme could mean memory, and the word "memory" is used in every single S4 episode. I don't think I caught an elephant in TLD, but then that ep had TD-12 to get the point across more blatantly. In T6T, the elephant is on the black-and-white takeaway menu on Mycroft's fridge.
- Back to the Red Child, Akako, I realised tis line had greater significance: "... So it seems you can live with the slightly blurred memory of Akako." I beleive someone on Tumblr has already pointed out S4 could be showing us the drugs taken on the plane in HLV affecting Sherlock's memory. This appears to strongly support their theory.
- A couple other things I noticed (there are so many!): In TLD, Sherlock says "I'm still falling." (sitting in Eurus/therapist's house, talking to John) as if referencing TAB's waterfall. Also in TLD, Sherlock's hospital room in Culverton's wing suspiciously resembles the living room of 221B. Could be a design coincidence, but it jumped out at me. The refraction of the moon (?) in the right-hand window kept catching my eye too.
I still have to rewatch TFP to complete the comparison, but I know where the glass elephant is in that ep. For right now, taking that Akako line into account, I'm wondering if the Redbeard twist is that it really was a dog all along, but Sherlock's drug-addledness turns the memory into a version of John since Mind-Palace-Sherlock keeps telling himself, "there are always two of us."
But seriously, all that 'secret sister' and 'it's never twins' stuff... Only way that can truly be a "groundbreaking" thing for television is if Euros is the feminine, softer, intuitive half of Sherlock's nature that he repressed long ago resurfacing, and if that repression turns out to be not because of the loss of his dog but because... trans Sherlock overcompensating to emulate his big brother, his main male role model until John came along and taught him to feel again.
... Just mah two cents.