It has to be someone whom Barry knew.
This is a signature.
We Are With You Zack Snyder
What if the Felicity in the limo was a hallucination?
Oliver has a history of hallucinating. Also twice in the past few episodes had a character hallucinate. Felicity saw her college self and Oliver saw Shado again.
Batman Ninja more like Batman's Bizarre Adventure
The key here is Felicity's reaction. She would not be asking Oliver to kill someone if the death was Constantine (brief acquaintance) , Nyssa (ally she's not personally close to), or Malcolm (why would anyone ever suggest him?).
And it doesn't actually matter if the audience doesn't care about the victim, only that the characters reactions make sense in-universe.
The only candidates that would give Felicity that kind of reaction are her mother and Oliver's son.
![[up]](https://static.tvtropes.org/pmwiki/pub/smiles/arrow_up.png "[up]"){kind=icon}
Not Thea? Or Diggle? She doesn't even know his son, or care about him.
Thea and Diggle know the risks of their lifestyle, their deaths aren't really something I can see causing her to be pro-killing.
Oliver's son is only on the table because it's still possible they could meet this season. Witnessing the direct murder of an 8-year-old boy she grew close too would be the only other way ,besides her mother dying, I could see Felicity wanting Oliver to kill someone.
I do think Quentin is the biggest target, followed by Diggle. They've already teased Thea and Felicity's death on the show, and Laurel would fall into Stuffed in the Fridge territory.
Remember that Barry also has to know this person.
Barry does not give half a damn about Felicity's mother. Also, it's not going to be Thea, because they're painting that too thickly. The best candidate is Diggle, with Quentin as a weaker option. He'd technically be the stronger option, if Barry was more familiar with him.
Hell, it might be Laurel. I strongly doubt that they'd do that, but it's a possibility.
Oh, and there's Roy.
edited 6th Feb '16 10:42:08 AM by SpaceWolf
This is a signature.
Eh, nevermind.
edited 6th Feb '16 10:48:04 AM by VeryMelon
Do we know for sure that the "him" in the future is Darhk?
edited 6th Feb '16 11:36:50 AM by KnownUnknown
"The difference between reality and fiction is that fiction has to make sense." - Tom Clancy, paraphrasing Mark Twain.
The dead person doesn't have to be someone Barry knows, just someone important enough to Oliver and Felicity that Barry would want to be there to offer them emotional support.
I still think William's mother is the most likely, probably happening in front of him.
It's a sufficiently heinous act that Felicity wants revenge in principle, especially if she's gotten fond of the kid and sees him destroyed by this. And she lives in Central City, so part of Barry's 'flock' and Barry did the DNA tests so he might feel more connected to the situation than just emotion support for his friends.
That or 
he kills Oliver, and we've been watching Oliver's soul possessing someone else. After multiple seasons of Batman, Ollie is now going to start stealing Deadman's gig. 
Never Trust
Maybe it's Felicity's mom.
Trump delenda est
X6 Barry cares about Felicity, he likely thus cares enough about her mum by proxy to care, however note that he personally wasn't looking particularly broken up, he seemed to be sad on Oliver's behalf, which makes sense if it's Felicity's mom (he'd also be sad on Felicity's behalf, but he was speaking to Oliver), or possibly her dad.
How Laurel Lance, BLACK CANARY, Helped A Fan Fight and Overcome Cancer!
http://moviepilot.com/posts/2846744?lt_source=external%2Cmanual
.
edited 7th Feb '16 4:43:04 AM by windleopard
Awww. That's absolutely wonderful.
Leader of the Holey Brotherhood
Now, this can't be for the Suicide Squad because we already know who's in it. I'm guessing Deathstroke will be saved for whatever is going to happen in the Titans show now that TNT dropped it.
edited 8th Feb '16 9:02:44 AM by VeryMelon
We Are With You Zack Snyder
There is a rumor that the Cyborg solo movie will become a Titans movie instead.
Ah, that would be the best way to salvage the concept. Cyborg can't hold his own film anyways.
The whole point of keeping separate continuities was to allow film and television more creative freedom, much like what the video game and cartoons enjoy. This is the opposite of that.
The concept of a multiverse has already been successfully introduced. If they're worried that general audiences won't understand the notion of alternate versions of even the most popular characters then the studio needs to stop hitting the reboot button so frequently.
Manu Bennet is also a main character on The Shannara Chronicles, so he wasn't likely to come back anytime soon anyway. Too busy.
The Cyborg movie being turned into a Titans movie is unlikely, as the movies are more or less based on the current Nu52 continuity, and in that continuity Cyborg never was a Titan.
edited 8th Feb '16 10:46:36 AM by KnownUnknown
"The difference between reality and fiction is that fiction has to make sense." - Tom Clancy, paraphrasing Mark Twain.
If anything Nu 52 was what they were anticipating the new movies were going to be. There's nothing stopping Cyborg from being the League "sponsor" for the Titans either.
Ah, don't blame them.
I blame the fact that the show is still trying to tell Oliver's island adventures nobody gives a sh't about, while also trying to tell Oliver's battle against Damien Dark whom no one, not even Malcolm with his league of ninja assassins seemed to give much of a sh't about, while also trying to tell us that Damien killed off a major character.
And since Felicity and Barry have been cleared, killing off Thea or Diggle would be too extreme, it's probably going to be someone I hardly give a sh't about.
Like Constantine. Or Nyssa. Or Malcolm.
edited 6th Feb '16 12:18:01 AM by Soble
I'M MR. MEESEEKS, LOOK AT ME!