Louie acerbically breaks down the family's adventures into three parts: "Whoa!" (The family discovers something incredible.) "Wait, what?!" (The incredible thing turns out to have some hidden trap, flaw or danger.) "Aaargh!" (The family have to flee for their lives from the hidden trap, flaw or danger.) Ironically, his efforts to just have a quiet game night end up the exact same way:
"Whoa!" We're just relaxing at home for once!
"Wait, what?!" Scrooge is ridiculously over-competitive, Huey is having a meltdown over his sewing skills, and Gyro has shrunk himself down to microscopic size with a shrink-ray and discovered a lost tribe living in the mansion.
"Aaargh!" The microscopic tribe have seized Gyro's shrink ray, declared war on the family, and are shrinking everything in sight!
Scrooge's adeptness at figuring out what Donald is saying during their Charades game makes a lot more sense. Not only do they have an extremely long history of adventuring together, there's also Donald's unfortunate speech impediment; given that adventuring would have often needed some clear, precise communication, it's reasonable that Donald would often have needed to use signs and gestures to try and convey things more clearly than his voice would allow. So, Scrooge basically has years of practice at reading Donald's Charades.
Dewey guessing and Webby acting:
When it's Dewey and Webby's turn at Charades, they flop hilariously on their first round. So of course they would've had Webby the one acting and Dewey the one guessing. Webby is admittedly very good at Charades, as seen when she accurately deduced Dewey's predicament in "JAW$" from Huey and Louie's hysterical gestures alone, so having Webby as the guesser would've made failure completely out of character for her.
They likely decided that Webby would go because she has training in various kinds of communication and lore. What they failed to account for was that Dewey had been leading on all of their adventures while Webby had been following his lead. The one time Dewey had to follow someone else's lead, he failed spectacularly. This is even foreshadowed in their song; Dewey and Webby.
It's also key that Webby's word is "Scrooge." While Webby and Dewey are very similar, they have wildly different views of Scrooge. Dewey focuses on him as the daring adventurer, "tougher than the toughies," discovering new places, fighting giant monsters, etc. Webby has a more rounded, complete view of him. She focuses on miming Scrooge on a daily basis (likely the same man she grew up witnessing while he was on his adventuring hiatus), namely his top hat and cane, counting money. Dewey doesn't associate those things with Scrooge (in addition to being a bit of a Cloud Cuckoo Lander in general). If Webby had been given a more adventurous word, she and Dewey would have been more in sync and he probably would have been able go figure it out, or at least his guesses would have been more on track. Reading a little more into it than was probably intended, there's also the fact that one of Webby's best friends didn't associate her with her idol. Part of her subsequent insecurity could be related to a fear that she'll never measure up to Scrooge (the same fear she later has regarding Della).
Fridge Horror
Just how many Gyropuddlians have been unwittingly killed by the everyday activities of Scrooge and his family, especially Mrs. Beakley and her cleaning? Admittedly it's noted that they are very fast at getting out of danger.
Scrooge addresses himself as "a billionaire" in this episode when fighting with the Gyropuddlians. But Donald once called him a Trillionaire in the pilot. Has Scrooge been losing money with all the adventures going on?
He lost plenty of money in the form of a rampaging money shark in "Jaw$!". But a trillionaire is technically also a billionaire - one that owns more than a thousand billions.
Also, Donald calling him a trillionaire could have just been a snarky exaggeration - it's the same vein as Scrooge being called a "bajillionaire," just a way of implying "he's really really rich."
The Gyropuddlians put a city on something that was floating in the toilet. Given that they don't seem to operate that much faster than the normal sized ducks, it's implied that whatever was floating in there was left there long enough for a small city to be built. Exactly how long has that toilet gone unflushed!?
Considering the mansion had only three occupants for ten years, it's probable that there are plenty of rooms that didn't get used in that time. Scrooge was basically going through the motions, so he'd have a set routine; Mrs. Beakley's idea of a good time is sitting around quietly reading a book, so she probably wouldn't be the type to go into different rooms without a reason; and while Webby's adventurous and "going into every room in the mansion looking for mysteries to solve" is in-character, "flushing every toilet in the house I've lived in my whole life" isn't. After Donald and the boys moved back in (and after Donald was explicitly banished from Scrooge's bathroom in "Daytrip of Doom!"), there would be every reason to start using different rooms in the house. So a toilet going unflushed for ten years makes sense. And if the lid was up, anything could have fallen in.
