As far as the Felicity part is concerned: I think its possible they might have planned to draw that storyline out, but there was a science article I read recently about an Australian company working on a very similar technology (one that could help those wheelchair bound walk again via an implant) which they will be conducting human trials for sometime next year. So my guess, they wanted to up the wow factor on Curtis's intelligence and also tie in the battery that Felicity is using to help her walk again. Also, they seem to prefer milking relationship drama over anything else. Personally, I think the whole 'curing her paralysis six episodes later' is a huge 'eff off' to the disabled community. Its very rare for a major character on a TV show to face something like this. I compare this to "Person of Interest" and the fact that Finch walks with a permanent limp, and I just find it in incredibly poor taste.
On the MG tweets front: I've honestly distrusted anything MG says with regards to the show since after 2x10 or 2x11, when he was asked by someone when Roy would find out Oliver was the Arrow. His reply was, "Not for a while." 2x12 comes along....
Now, me, looking at this more clearly, I just don't see this being anything more than another of MG's big twists. Something to consider, here, is that whatever is going down will be a huge blow to Team Arrow, and Oliver is swearing vengeance on 'him' (presumably Malcolm unless DD escapes during his trial). Whatever happened could have causes several injuries; perhaps we'll even see Quentin, Donna, and Laurel all in critical condition in episode 18.
If the title is, in fact, "Canary Cry", there is the fact that there is always some dual-nature reasoning to these types of titles. In "Deathstroke", we thought we would see a battle between Oliver and Slade, but it was to showcase the other aspect of Deathstroke/Slade Wilson, his tactical planning. In "Al Sa-Him", they did a very good job, up until those last few minutes, of Oliver seeming to be completely in the thrall of Ra's Al Ghul. Then the bio-weapon was revealed and with Ra's unable to see his expression, we saw the real Oliver, thus revealing he was once more employing a risky gambit, just like he did in the Season 2 finale with regards to Felicity and the cure to fool Slade.
Also, it would be in pretty poor taste if they had the funeral episode titled "Canary Cry" if the person who uses it (Laurel) is dead at the end of Episode 18, unless they're planning on someone else taking up the mantle. The problem here being that the only person who could without them losing a whole lot of fans (and they'd lose fans regardless) is Caity Lotz, and frankly Sara/White Canary is growing much more on LoT than she ever could on "Arrow". I've said this elsewhere, but if they're foolish enough to do something like having Felicity look into taking up that mask (despite MG's vow that Felicity will never have a costume while he's showrunner, one of the few things I want to believe coming from him), than that will be what makes me leave this show behind and just watch Flash and LoT, with only crossover episodes being my Arrow intake. Its one thing if they want to continually eff with the Lance family. Its quite another to have a character who has no connection to the BC lore in any fashion take up that name.
Oh, and I only bring that up because I've actually seen fanfiction like that and it makes me sick to my stomach because these are many of the same people who make up MG's Tumblr/Twitter fanbase....
