So, I'm not going to go over the theory that the Striaton triplets would be the Shadow Triad, everyone and their Growlithe has heard about that.
What I'm going to talk about is this:
(Well, the first few minutes of it.)
B2W2, and in particular, the triplets' Memory Link flashback is widely stated to disprove the theory. And I mean, obviously, it's literally showing that the triplets and the ninjas are different characters.
Except it's also literally saying and showing the opposite.
This short scene raises a staggering number of questions and is just plain odd on a number of points:
First off, they're still talking about that a year later. Okay.
They mention N, the Sages, and the Shadow Triad, specifically and by name, despite (supposedly) never having met any of them.
Cress immediately identifies the Shadow Triad, despite (supposedly) having never seen them.
The Triad not only give no reason for why they're there, but insist on the fact that they have no reason to as if to counter-justify it idk it's just really really odd.
The triplets's reaction to not being considered good trainers or Gym leaders... was to give up the Gym... and keep the restaurant. Not, you know... give up the restaurant and focus on battling. What.
To note: so far, all the other Gym Leaders who have been known to give up on their Gym have been: people who were getting older and ceded the Gym to a family member or apprentice (Falkner and Jasmine's fathers, Flannery's grandfather); Koga who got a promotion to the Elite Four and Wallace who became the Champion (and again, both ceded the gym to a family member they personally knew the power of); Lenora, who decided to focus on a different passion of hers and stopped Pokémon battling, and entrusted her gym to someone who had defeated her as well as the E4. So, either stopping Pokémon training and battling all together, or advancing further in the trainer "career". Being a Gym Leader is one of the best ways to get better, all Gym Leaders see their role as an opportunity as well as a reason to keep getting stronger. Stopping that to become stronger makes no sense.
Unless you're Giovanni and you're a member of an evil team — oh wait I mean...
Yeah just in general Pokémon trainers who aren't Gym Leaders and want to become stronger don't friggin stay home in their comfort zone training amongst themselves. Red, Giovanni, Steven Stone in Emerald and ORAS, Cynthia in her cameos, they travel and meet people.
Speaking about successors, the end of the scene suggests that it was Cress who proposed Marlon as a replacement Gym Leader. You know, the guy who, one year later, actively refuses to help against Team Plasma when he is right there.
The Shadow Triad literally say Ghetsis is planning something again. A year before B2W2. And the triplets didn't apparently tell anyone, and when something did happen, they didn't join the fight.
Their reaction to hearing that is to give up being Gym Leaders. Elesa's line while challenging the Sages (see video linked below) is that, as Gym Leaders, it would be shameful to ignore Team Plasma.
And finally, a multi-layered point: this scene is allegedly taking place a year after BW. One year later, they're still talking about the fact that they didn't go to N's Castle. But there is still no bigger reason given as to why they weren't there, aside from that "Bianca got to them late". Even back in the first BW games, it was very, very weirdly handled.
There is this amazing exchange between Cheren and Bianca in the epilogue of BW:
Bianca: "... I'm sorry. By the time I went to get the Striaton City Gym Leaders, everything was over..."
Cheren: "If that's the case... I let Ghetsis escape when the Shadow Triad created an opening."
Bianca: "[?] ... Ghetsis? The Shadow Triad?"
That's one pretty conspicuous juxtaposition right there.
Cress is the only Gym Leader whose post-game dialogue mentions the incident at N's castle... and still gives no other reason than "heard about it too late". Actually, the way it's worded is also just... really, really weird.
"...We heard about the incident with N's Castle. If we had received the message in time, the three of us could have helped."
Like, he says this like they just heard about it a long time after the fact, and it's never stated that Bianca actually met up with them or saw them while the castle thing was going down. In the French version, it sounds even more like they were just supposed to get a message (possibly by Xtransceiver), and never did.
There was no meta reason for it, either: the Gym Leaders already outnumber the Sages, at 8 versus 6, so it's not a matter of making that battle fair. Actually, there are three free spots between them. The configuration is pretty weird (which Gym Leaders are fighting which Sages, exactly?!), and having the Striaton brothers join would at least have allowed them to stand as one long wall-like line, though at 11 vs 6 it would still have been a slightly awkward match-up — but Clay is clearly acting as the leader, so he could have been the one battling alone with everyone else pairing up and having a tag battle against each of the 5 remaining Sages.
The guidebook talks about it. I have personally looked through an official BW guidebook and in the pages about the events at N's castle, there's a little box wondering why the Striaton City Gym Leaders weren't there and what that could mean.
It's not even played as a joke about how the brothers can't catch a break. The games drew attention to it and deliberately put it in a suspicious light. And B2W2 gave no follow-up... but called attention to it again, only if you'd played the previous games (as the Memory Links are only available by syncing data from a BW game).
But still didn't give it a reason.
What I'm saying is: if you wanted to tie up these loose ends and completely remove any possibility of the Shadow Triad being the Striaton brothers, is this how you would have done it?
Because personally, the first thing I'd have thought of doing would have been to bring in the triplets to help during the climax of the struggle against Team Plasma. They could have helped stalling the Dark Trinity, in the same way the other Gym Leaders stalled the Sages 3 years earlier. This would have been a nice echo and a very satisfying way to tie up the triplets' character arc, allowing them to finally prove themselves — and could still leave us to battle the Shadow Triad later in Icirrus City. They could also have sent only one or two of the triplets; this could have been a nice reference to the anime, in which Chili and Cress run the Gym between the two of them in Cilan’s absence. In one episode, Cress is even left to temporarily handle the Gym alone, and Chili reveals that he wishes to open his own Fire-Type Gym — either of them staying would have been a cute, subtle reference.
There were many opportunities and ways to bring in the triplets and have them resolve this arc during the plot, and it's honestly strange and suspicious that this isn't how it went.
What happens instead is that Cheren comes in to help against Team Plasma. Cheren, who:
lives on literally the other side of the country, while Striaton is closer to Opelucid and much closer to Humilau
has just started a new job as a Gym Leader and as a teacher and is really a lot busier than the triplets, who are only running a restaurant anymore and could at the very least have spared to send one out of the three of them
already proved himself against Team Plasma numerous times in the previous games
— Cheren, who has plenty of excuses, in-universe-wise, and no need, meta-writing-wise, to be there.
More importantly, this would have actually happened in front of our eyes.
Because what's really going on in this scene is that Cilan is telling you this.
It's unclear what the Memory Links are supposed to be exactly; there are at least two cases that seem to be flashbacks telepathically transmitted into the player character's mind (the ex-Plasma Grunt in the Pokémon Center, and Zoroark). But here, Cilan explicitly mentions that he's telling us this, and there is at least one other case of a character just recounting an event (Skyla: "Since you're here, I'll tell you a little secret!").
Remember you're not playing the hero from two years earlier — Rosa/Nate has never met Cilan. But Cilan tells a complete stranger, unprompted, about how, one year ago, he and his brothers battled people whose existences and appearances they shouldn't have known.
Someone who can be suspected of being a mole to Team Plasma goes around telling random people that hey we're completely different people by the way. I'm just telling you this for no reason. Not that there's any external witness of that. Not that there was any reason for that to happen in the first place, either.
Why anyone considers that scene to be proof of anything has honestly been beyond me for years, because it actually just makes the triplets even more suspicious: by having them reveal that they know of the Shadow Triad's existence, by having them bring up their absence at the Castle again (admitting that it was important), and by not having this actually happen in front of our eyes when it could have, when there were good reasons for it, when it would have been the straightforward thing to do.
Instead, fans cried out that this was anything from accidental unintended hints to the writers changing their minds at the last minute and not managing to make up for this. In short, bad writing. But if this was deliberate, then it's actually pretty good writing — on par with the writing that the games of Generation V got overall on all other accounts.
The Memory Link gives the possibility that the Striaton triplets really did battle the Shadow Triad one year ago and that the six are different characters.
It also leaves open a very real possibility that Cilan is lying, which he would only have a reason to do if they were the same people. It pointedly does not irrefutably disprove the theory, and in fact seems to give some more hints and support for it.
It's difficult to say which is "more canon" or "intended to be canon". It's even difficult to say that the games take a stance one way or another. They really don't. If you don't like the idea, you can decide not to believe it — you are absolutely justified to! The video supports that!
But it doesn't actually say that is the one and absolute truth.
Not-quite-as-relevant-but-still-sortof:
I can't actually confirm this because I can find no source about what blocks off the way to Striaton City in B2W2 until the postgame but I have this striking memory that it was a friggin Stunfisk infestation, that this was the reason B2W2 gave as to why the triplets didn't make it this time. I may be wrong. But if I'm right, what in the Arceus-loving hell.
(May I remind you that Stunfisk is basically the Trollface Pokémon, by the way. And that it's strongly associated to Cilan thanks to the anime.)
Amusingly, though I haven't managed to read all of the BW Pokémon Special manga, last I heard of the Shadow Triad in it, they were battling the Striaton triplets... but again with no other witnesses nor particular reason.
If you don't believe that Cilan was just saying something and that there's no way he could have been making it up, and you consider that all the Memory Links are absolute truths and objective memories of people who were present at the time, then I hope you take it as canon that N's a Zoroark.