Sherlock has a dog.
Remember Redbeard?" The elder Holmes brother had asked him, to which Sherlock replied, "I'm not a child anymore, Mycroft."
Redbeard is actually Sherlock's childhood dog. This isn't just a seemingly insignificant detail for the detective, at least in Mycroft book. The same name was also mentioned in Magnussen's "file" of Sherlock.
The dog became more significant when he looked to a memory of himself petting the Irish Setter to keep him calm when Mary shot him.
Apparently, the dog was used by the season three villain as a "pressure point" for Sherlock.
Sherlock and Lady in red.
Sherlock Holmes (Benedict Cumberbatch) was spotted with Sian Brooke while shooting in London, and according to reports, Brooke's character might be one of the detective allies, Cumberbatch appeared to be jolding a piece of paper which might be a script or a prop from the show.
Enola Holmes is the younger sister and youngest sibling of Sherlock and Mycroft Holmes. She appears in the series The Enola Holmes Mysteries by Nancy Springer and it could be inferred that she appears in the story The Copper Beeches as Violet Hunter, however there is not enough evidence to support the fact. Enola is a very independent and rebellious girl who likes to wear trousers while riding her bike. She becomes a Perditorian, or finder of lost things, when her mother runs away with the gypsies and her brothers try to send her to boarding school. Using her natural cunning which seems to be inherited by every member of the Holmes family, she creates multiple disguises on her quest to be reunited with her mother and evade her brothers.
Anderson and the army troop
Anderson was full of guilt after Sherlock Holmes fell from the roof of St Bartholomew's Hospital, believing that his belief that Sherlock was a fraud led to the fall. Philip eventually lost his job after his theories about Sherlock's survival began, also growing a beard. He created a fan group called The Empty Hearse, a group of believers in Sherlock Holmes. He tracked what he believed to be Sherlock's travel across Asia and Europe, from cases in the Himalayas and New Delhi to closer ones in Continental Europe.
So..Is he joins army now?
Molly in disguise