Okay, so know that I have heard some rumors about a season 5 – though I found out about it like five minutes ago and still don't know much about it – I tought that I could share my theory about Molly’s boyfriend, Tom. It also includes some ideas of what might happen in season 5 (if there is one). (I have just copied my text from reddit and I haven't read it since I wrote it so if there is some grammar mistakes etc I apologies for that. And maybe this text and theory just sound weird...)
So, I have this theory about who Molly’s boyfriend Tom really is. When I did som research for this theory I found some other posts with theories that was quite similar to this one, but as I think I didn’t found any that included all parts I decided to share my theory and thoughts to.
So, when Sherlock first meets Tom (in the Empty Hearse at Baker Street) Sherlock clearly remarked something about Tom. And we can also see that Tom looks and dresses like Sherlock. I, and probably Sherlock too, think that Tom is the “Sherlock Lookalike” that Moriarty used in The Reichenbach Fall when he kidnapped the children. Why else would BCC and Moffat and Gatiss make Tom look so similar to Sherlock? And why else would Sherlock look so concerned when they first met?
But I also think that Tom is Sebastian Moran (Moriarty’s friend and colleague in the books) because if Moriarty didn’t know and cared for the lookalike then he would have been killed after the work was done, as Sherlock said in TEH. And yeah, I know that Sherlock said that they used the lookalikes dead body when they faked Sherlock’s death, but I think that Sherlock either lied (and they faked the death in another way) or that they found another body with they assumed were the body of the lookalike.
And when Sherlock and Molly talks about her new boyfriend in TEH and Sherlocks says that “not all men you fall for can turn out to be sociopaths”, I take that as a hint that Tom is in fact a sociopath (or a psychopath, or at least not on the side of the angels) too.
But there’s more, the assassin in TRF who is supposed to shoot John (if Sherlock didn't jump) could be Tom. We can’t really se his whole face due to the dark and the camera angel but from what we can see the ha looks like Tom. And the fourth assassin who moved in near Baker Street and whom Mycroft warns John about (in TRF) also looks like Tom. So two of the assassins that work for Moriarty looks a lot like Tom, and I take that as evidence that Tom works for Moriarty, and probably is Sebastian Moran.
But then why did Tom get together with Molly? I think that it was his job to fulfill Moriarty’s plans after Moriarty died. And in order to help Eurus with the Final Problem he had to gain information about Sherlock, and did so by pretending to be Molly’s boyfriend, just like Moriarty did in The Great Game. And when he had all necessary information he broke up with her. I also think that Tom/Sebastian would make a great villain in a season five, by taking over Moriarty’s businesses.
