You know when something has zero arguments stated to support it, then it really are not spoilers. The only difference with this and a fanfic is that a fanfic acknowledges itself as being a fanfic.
Now this vid is one of the better ones I've watched. Normally the uploader thinks that just because he is in a video on YT, somehow that makes what he says more credible and becomes oblivious to the flaws in what he says. Still this guy fell for two tricks, namely not differentiating between what you wish vs what makes the most sense (albeit he has admitted to this) and secondly for the concept of subliminal advertising. The latter refers to hiding images with suggestive ideas inside a commercial that are too fast to be seen with the naked eye, but somehow get absorbed by your subconsciousness. Now it's still a matter of debate whether this actually works or not, but anyway in regards to what is told in this vid, something similar is used and in particular to the whole Luffy-dies-and-gets-resurrected-by-Law thing is a prime example of that and several people in this thread fell for it too. It's not what is described in that FB post that makes sense, it's the reasoning that's behind it that make sense: it's kinda pointless to give Law that immortality ability and then forget about it, so from the moment it was introduced there was and is a reasonable chance that Law would have to use it someday, which automatically gives rise to the question which person would be important enough and then you automatically end up with Luffy. That this might happen someday is plausible, however everything else that's written in regards to when, how, why etc. is baseless, but of course because the underlying reasoning is acceptable, you automatically accept everything else as being plausible too while the truth is you could easily create countless of different scenario's based on the exact same reasoning.
Once you realize that, then you see it falling apart. It's a nifty trick that's often used with theories like these to fool people as even when they have proven to be bogus, you can still claim that it's partially correct due to underlying reasonings and saying that it's impossible to get everything correct. Though logically that's a stupid excuse as everyone can make such vague predictions.
Anyway now back to the FB post this subliminal advertising is something that's used quite a lot of times here and to determine the credibility of it all, you need to ask the right questions, see which information is there and which is not etc. and when you do that, these "spoilers" start to fall apart piece by piece.
For starters the source. The vid guy already said it, the source is as unreliable as they come. A supposed former graphic designer of OP leaked this. Now I reckon they have their methods to keep information from leaking, so that a former employee still was able to do it, is already quite questionable. Then that employee supposedly posted it on an internet forum clearly stating what his profession was, because apparently that's a clever idea, and then that post gets translated into another language (which is already a hassle as no matter how good you can translate, there will be mistakes) to eventually end up on FB where it goes viral. As a source this is a joke.
Secondly the Whole Cake Island arc. The vid guy again already said it, the lack of details is nonsensical. Logically the further away you would go from the current arc, the lesser details there would be and the vaguer the plot would become as it's impossible to say exactly what's going to happen in the far future when you don't even know what's going to happen in a few chapters. However somehow these spoilers are the complete opposite of that. The further the events that are mentioned are, the more detailed they become. That makes no sense. Most of the things that are mentioned are actually possible, but they are simply so vague and without context they're worthless. It's plausible that Jinbei and Pudding aid them. It's plausible that Nami uses the Vivre card to escape the forest. It's plausible Luffy beats Cracker but ends up unconscious, but everyone who reads the series could have made these.
The only thing that stands out is the whole Sanji reconciling with his family. They never had an argument to being with, they always hated each other from the start, there is nothing to reconcile about. If Sanji wouldn't have been useful to get into an alliance with Big Mum, they wouldn't even have bothered getting him back. So it makes no sense that now suddenly the Vinsmokes would protect Sanji from the person they wanted to ally with. Adding to that there's no mentioning of the poneglyph or Capone. What's also peculiar, is that the spoilers conveniently start exactly on the moment where we are now in the series. Meaning someone should have written this recently while the post is kinda vague on the timeframe, but if this was indeed written recently, there should simply be far more details.
Thirdly the Wano-arc. There is no mentioning of an actual storyline on Wano, like the only thing they did on that island was fighting Kaidou, while that's not the way Oda writes. It's also not normal that they take a 2 week break to train as outside the time-skip, they never deliberately had a time-off for training. It's also a running gag in the manga that Luffy can't follow strategies, let alone sit around for two weeks and then to get into a fight where apparently no real strategy is even used. Marco and the remnants of the WB pirates aren't mentioned here either while the two dukes are which is weird considering they were searching for them. It wasn't clear what happened to Hawkins, but only Kidd was jailed while Apoo seemed to have joined Kaidou, so why are they in jails? And where is Drake?
The vid guy already mentioned something similar that normally Zoro's fight is always the last one finished before the final battle reaches it conclusion. For some reason though he now finishes first? And by using an eye-power? That Zoro can open his left eye, has been suggested ever since the time-skip. So this really feels like it was solely added to give people something they want to happen rather than it being plausible. Oda confirmed that Zoro's specialty is CoA, so why is he having a special CoO power and why only in one eye? And why would it fatigue him? And in regards to the other calamities why did the Strawhats wait that long to step in? Why didn't they help from the start? And how do you make a fight last three days? That's something that works when you make a time-jump or when you described a fight that has already occurred, but you can't do that with important battles you follow from beginning to end. And again no mentioning of the poneglyph.
And then you have Luffy's Gear 5th. Ever since the Gears got introduced, people always speculated on the next one in line and this is going to remain like that as long as there is a next battle to fight. What's important here is that it's not explained what Gear 5th does. Every Gear does something unique, that's the whole point of it and still it is not explained. They explain it has a time limit and has a recoil, with other words something all the Gears have or had at the beginning, but not the most important detail of all. This is one of those things that simply should be in here if it was true. Same thing with Kaidou's ability, it's not mentioned. It doesn't matter whether he has a DF power or not, his fighting style should be based around something and don't tell me Oda has no clue yet about that. The funniest part though is that suddenly everyone breaks their bones. Many characters received numerous severe injuries, but I don't think Oda ever described broken bones. It sounds silly, but it's easier to imagine that someone can keep on going while being stabbed and shot rather than having broken legs. You can't stand if they are broken, but somehow Luffy breaks every bone in his body per hit when he uses Gear 5th, but he can keep hitting? What?
And then lastly the Marineford arc 2.0...this is by far the most ridiculous thing in the entire post. This doesn't just look similar, it is the Marineford arc. The overall concept, the way how certain characters react, the sequence of events...it's the exact same thing, only someone swapped Ace for Luffy and then added all his fantasies. However if this would be true, the story just got massacred. After an event like this the world order is shattered. That would make the entire quest for the OP, Raftel and the Pirate King almost pointless. Also what happened to the Reverie? The most striking thing though is that the spoilers end on the exact moment the battle is about the start. I mean really? That's what you do when writing a story and end the chapter to make people anticipate the next chapter, not when you explain everything that's going to happen the next 5 years and then bolt when the real thing starts.
No this is a farce. Spoilers my ass. At the very best someone used predictable and vague storylines coated into wishful thinkings to fool people into believing this is credible. The fact that it went viral shows that he pretty much succeeded.