Scrooge recalls the events of the Treasure Of The Golden Suns arc to Donald Duck & Della Duck. That Story arc also happens to be the "First Adventure" of the original DuckTales series!
Similarly, Yellow Beak originates from Donald Duck Finds Pirate Gold, the "First Adventure" of Carl Barks' duck comic career.
Scrooge comments in the epilogue of this episode that Mrs. Beakley trusts Bradford, which is a rarity for her according to Scrooge. That may explain her extremely protective behavior in "Escape from the Impossibin!", in light of the family learning about Bradford. She is freaking out over being so wrong and overcompensating.
Bradford's original name for his organization was O.W.L. Aside from the obvious bird pun, it also reflects the kind of organization he wanted to create and direct; owls are (usually) nocturnal birds, popularly known for their intelligence, and, thanks to their cushioned feathers, their flight is so silent that prey don't hear them coming until it's too late. Bradford wanted an organization that focused on pragmatic, well-thought schemes, operating from the shadows, and handling all threats in unnoticed, efficient manners.
Black Heron, on the other hand, insisted on making it F.O.W.L.; the fowl birds include game and water ones. Black Heron's mindset amounts to “go big or go home”, and, for her, world-conquering and villainy aren't just careers, but a life style that is meant to be fun for those practicing it, making it a big game. And, of course, herons are waterfowl.
Of course Bradford will keep Black Heron in F.O.W.L. despite disagreeing and arguing on a regular basis; she's a co-founding member. While Bradford calls the shots, he knows he needs Black Heron's supervillainy experience to make it work on the long term. In the present day, with Bradford now having much more experience and financial backup, while still keeping Black Heron around (again, due to her experience and skills), he makes it clear that he's the one in charge.
Seeing the Papyrus of Binding in action explains a lot as to why it always changed hands despite its power. The previous owners either knew that it would backfire horribly on them while the ones that did actually use it suffered the consequences trying to do so.
Black Heron wanting to watch Scrooge and his "sidekicks" fall into her trap is actually a good idea. If you set a trap for someone, its best to see if it worked. If it did, that's all there is to it, if it didn't, better to see it so they're less likely to take you by surprise.
As seen from this episode, Della acts a lot like Webby: bubbly, optimistic, obsessed with danger, and even having shades of her Genki Girl-level energy. This might explain why Scrooge never bothered getting to know Webby better before the triplets arrived—she reminded him too much of Della.
Now we know for sure Violet's fear of vampires isn't improbable; not only do they exist, but they exist as a race that isn't as uncommon as you'd think, hence Duckworth mentioning them as if they were another political entity.
Della being able to fly the plane on her first try explains why she was so eager to let Dewey try it in "Raiders of the Doomsday Vault!". She figured if she could do it, why couldn't he?
The climax has Bradford write on the papyrus "As far as the Ducks know, Bradford Buzzard was never here." It affects Donald and Della as expected because they're Donald and Della Duck. What's not expected is that it affected Scrooge too even though he's not a Duck, he's a McDuck which may confuse the audience. However, given Bradford knows how the papyrus works, he probably knew he had to mean "Duck" as a species, which Scrooge is and not "Duck" as a family name.
Ludwig Von Drake playing with a Rubik's cube in the 1960s is not necessarily error on the writers' part: it could mean that S.H.U.S.H., like many secret global organization in spy movies, have access to technology a few decades in advance of their time.
Fridge Horror:
Bradford’s vehement stance against chaos casts some of his decisions and behavior from previous episodes in an even worse light, such as halting the search for Della after ten years have passed. It’s more than likely it wasn’t just about losing money, but rather he didn’t want Scrooge to bring Della back, PERIOD. He’s personally encountered Della himself and he knows what a reckless wildcard she is and who proved to be a legitimate threat in her own right. Bradford is smart enough to know from what he’s seen it takes a lot to bring Della down, so he’d never believe she’s dead. That being said, leaving Della stranded would’ve meant F.O.W.L. would have one less wildcard to deal with. Donald on the other hand would be easy to deal with because he’s the one stuck with all the bad luck.
Donald also gave up on adventuring and only reentered Scrooge's life recently. So for years, Bradford had no reason to go after Donald.
In the finale, this is confirmed - Bradford not only wanted Della gone, he lead Della into taking the Spear in the first place.
The fate of Yellowbeak is both sad and horrifying. Imagine being a pirate captain who's found an amazing treasure that will grant you anything you want: Fame, fortune, power, and the very fabric of reality in your control. But the minute he uses it, he gets a rude awakening to its disastrous consequences: stuck on the tip of a mountain with no possible way to escape, and the simple, desperate wish for water causes his entire crew to drown, leaving him the only survivor. Rather than waiting to die of either hunger or thirst, Yellowbeak uses the papyrus to end his life right then and there (and knowing the papyrus' Literal Genie temperament, who knows in what horrible way he finally ended up dead?). But it doesn't end there—despite his clear wishes to stay dead and escape his torment, Yellowbeak is revived by Black Heron as a sickly puppet to defeat the McDuck family, during which his bones are scattered and tossed down into the abyss below, never to be whole again. Talk about a Fate Worse than Death!
To make this even worse? There's nothing to say that Yellowbeak lost sentience when he was tossed over the edge. For all we know, he's still on that mountain, forced to live all alone as an empty shell for eternity.
Black Heron wrote in the papyrus that Scrooge's "sidekicks" would perish on the mission; while it did not affect Donald and Della, due to being family on an adventure, if Scroorge goes on an actual mission with actual sidekicks, would the papyrus have a late effect?
The Papyrus being literal operates on logic and it will assume time based on the command wording. Like a computer, it will stop working if it can’t interpret certain verbiage. Heron said “this” mission, not “a” mission, meaning a present, not any future mission. The only mission happening was Black Heron’s, so it would’ve picked that up, but the word it couldn’t interpret was “sidekicks”. Since Scrooge doesn’t identify them as sidekicks, it stops working at that word. That being said, it means the Duck Twins were just one word away from being killed.
If Donald ever used the Papyrus, his luck would be just as bad as before. He’s the unluckiest Duck in the world, not even the Greek Gods can break his streak. If Donald commands the papyrus to get a job, he’d get fired from it after a day or two. If he wished for a job he won’t get fired from, he’ll be given an idiot-proof job he absolutely hates. If he wished for people to understand him, he’ll likely get a more coherent voice, but one that is loud, booming and packs a punch, and/or everyone he speaks to will take him very literally/agree with him for no real reason. Really, the scroll wouldn’t do any harm for him, he’s too unlucky and too foolish to come up to come up with desires that will long-term change his luck in a good way.
Fridge Logic:
Hypothetically, you could fix the problems with the Papyrus by writing, "From now on, the Papyrus of Binding will work exactly in the manner its user intends".
Would this REALLY be safe to try with a Papyrus that can, in fact, KILL ITS USER?
