It's a movie about time travel.
I'll grant that time travel is a decent prediction; probably some inside knowledge. Though also, not in-and-of-itself necessarily problematic.
Younger Indy features in it.
Young Indy is barely a stretch considering we already got him in LC plus a TV series, digital de-aging is in vogue, and Ford's advanced age was obviously going to be at the forefront of fans' concerns. Frankly, I would've been surprised if #5
didn't include young Indy. And we've known this, or at least presumed it, since nearly the first leaked set photos. Again, though - not necessarily problematic.
PWB is Indy's new co-star (and possible replacement).
Was he actually the first to break the news of PWB's casting?
The bad guys are Nazis with their time-travel bell thing.
The bad guys being Nazis is no stretch at all for a final Indy film - it's been my guess for a hypothetical #5 ever since KotCS's Russians were met with lackluster enthusiasm, and it was similarly revealed amidst the earliest set photos. And who can argue with Indy + Nazis?
As for Die Glocke, I've yet to see confirmation that the film adheres to that specific theory. But, if we've got time travel, and we've got Nazis... then that seems to be the default in public discourse of recent years.
If Doomcock was just getting lucky with all that guessing, then he should be picking lottery ticket numbers instead of Youtubing.
So I'll give points for time travel, and I suppose if he genuinely broke the news of PWB being in the film. The rest isn't lottery-level guesswork.
And again, none of these scoops are anywhere near the bombshell-level of Indy getting replaced/retconned, nor have any of them been denied.
I just don't see the logic in surmising that since a couple of medium-interest reports met with zero denial turned out to be correct, therefore a highly controversial report met with emphatic denial is probably likewise legitimately-sourced. It's possible, sure; but the latter doesn't naturally follow from the former. And if Disney/Mangold
are telling the truth, then either denying the replacement/retconning claims or remaining silent is literally all they can do, short of releasing the last twenty minutes of the film.