It makes sense that Huey would be the first to grasp something was wrong when he saw his Guidebook pages were blank. He admits in "A Nightmare on Killmotor Hill" that he's not great with imagination so seeing his book blank would be a warning sign rather than a cue to ad-lib or follow a script because he's not creative enough to think of doing so and the mental filter to accept the sitcom setting precludes him from realizing he's in a sitcom.
It's also a hint that the Guidebook is only a prop. There's no point in writing a book if the audience will never get a good look at its interior. Huey's "actor" is expected to hold the book so the audience can never see inside it. A higher-budget show might have used a book full of lorem ipsum, or gotten a hardcover out of copyright and put a new dust jacket on it.
Gene made a note of how the wish would try to preserve itself by any means necessary, even if it means getting hostile. The fact that Goofy gave Donald some useful advice encouraging him to undo the wish should have been the tipoff that he was actually not a part of the wish but real the whole time.
It can also be viewed as the wish pulling from reality to fulfill the concept. Della is surprised Goofy is there, but a normal sitcom episode requires some kind of zany situation to be resolved. Donald's wish is the zany situation, and it got the normal well-timed epiphany from a friend for Donald to realize his mistake.
Donald having a "normal" voice in the sitcom world is probably part of his idealized version of himself, just like his desire for a normal family. In his ideal world, he would never have to fight to be understood. He's also less of a Butt-Monkey in the sitcom world than he was in the real world.
Why was Goofy pulled into the wish? It's likely Donald considers him Family. Or possibly just a friend...or, Gene did it because of the urge for a "Guest Star"...
Likely because Goofy is one of his more normal friends who has the mundane life and family Donald wants.
From the ducks' perspective, Goofy is pretty much a regular guy (in his own classic cartoons he's The Everyman). But from our perspective (and therefore Gene's) he's an exciting guest star.
Gene is pulling ideas from Slice of Life '90s sitcoms. Goof Troop was an animated Slice of Life '90s sitcom. The Drop-In Character is a signature trope of the sitcom format, and in Goof Troop, that character was usually Goofy.
Of course the studio audience watching Quack Pack is a bunch of humans. Because in real life, the audience for Ducktales are humans and not sentient bipedal animals.
Despite being a joke, the Pet Snake thing being a bad idea is actually pretty interesting, as while nonvenomous snakes as pets aren't dangerous (unless they are particularly large constrictors that should not be handled alone), some species are known to become ill highly easily if not kept in very specific conditions, require high maintenance, and are hard to feed. While other species are comparatively hardy and low maintenance, they still have a few special requirements compared to dogs and cats and so at the very least keeping a snake as a secret pet is a HORRIBLE idea.
Which also adds to the joke, as said specialized nature makes a snake an even more out-of-character choice of pet for Louie.
The triplet who would want to keep a dangerous pet is Dewey. But since everyone's undergone Flanderization into one-note 90's sitcom clichés and Dewey is already the showboater, someone else has to be the troublemaker.
Moreover, the show's already done a "triplet tries to hide a weird pet from the family" episode in which the perpetrator is Huey. That was a B-Plot to an episode very concerned with emotional manipulation and exploitative relationships, where Louie's attempts to expose Gavin / Tenderfeet's scam to his well-meaning but naive brothers mirrors Lena's growing reluctance to trick Webby only to be exploited herself by Magica. One, this is further evidence that this isn't a good storyline for the "real" Louie, and two, the sitcom world simplifies the family's life by draining it of its full thematic weight and emotional richness.
Why would Donald like the idea of living in a sitcom like 'Quack Pack?' Because, if Della's naming choices were any indication, both were 90's kids. He just liked the 90's sitcom side of it a lot at some points: heck given the chaos in his life it was probably comforting to him and as an adult he found them even more appealing.
This is backed up by Word of God stating that Donald and Della are 36. Assuming the show takes place anywhere from 2017 to 2020, this means they were born in the early 80s, and would have spent a sizeable chunk of their childhood and all or most of their adolescence in the 90s.
Why isn't Duckworth part of Donald's ideal normal family life? Perhaps part of it is that he doesn't consider Duckworth as close a member. Or maybe it's because despite being secure in the mansion, Donald's ideas of being normal are pretty mundane without the stresses of being too rich. Having a butler in the house might not play well to the sitcom materialnote unless you've watched Mr. Belvedere, and having a Ghost Butler would be way too different for Donald's wish to work.
Why is Mrs. Beakley, who is obviously a less than normal addition to the cast, allowed into the wish then? Possibly because Mrs. Beakley is at least trying to act normal and keep her past behind her.
Upper-middle-class families on TV frequently have a housekeeper (The Brady Bunch, The Jeffersons). When a butler appears in a sitcom, it's either the "situation" of the sitcom (Mr. Belvedere, Benson) or the character is incorrectly treated as a male housekeeper rather than a staff supervisor (The Nanny, The Fresh Prince of Bel-Air). Since Gene is downplaying Scrooge's wealth to keep things "normal," having a housekeeper is a lot more believable than a butler.
Gene basically had two choices if he included Duckworth. He can leave him as a ghost, which would change the sitcom subgenre and be decidedly abnormal. Or he could raise him from the dead, which would have been even harder to overlook than Donald having a normal speaking voice. (Since Donald is so sensitive about his speech impediment, Gene had to fix that. Nothing similar applies to Duckworth.) Easier just to drop him from the cast; he's absent from the mansion enough that the family wouldn't find his absence noteworthy.
Beakley is in the flashback and in the ending. Duckworth isn't. He just wasn't on this adventure.
Seeing how out of control his first wish went, it was wise of Donald to use his last wish on something much smaller like a picture frame. There’s no telling how Gene, no matter how much of a good guy he is, will interpret another big wish and if said big wish will try again to protect itself if it feels it’s threatened. A small wish like wishing for a picture frame though is very easy to understand and is unlikely to backfire.
One of Louie's suggestions was wishing being a genie himself. Of course Donald won't do that unless he wants to be stuck as a servant. Ask Jafar how that turned out.
Building on to the above, it makes sense for Louie to be the one to make that suggestion. After all, he's the greedy one among the trio, and Jafar made that wish due to his greedness (albeit for power instead of money in his case).
Also, "The First Adventure!" reveals that a young Donald's very first adventure with Scrooge and Della involved a magical papyrus that worked as a Literal Genie, so he knows how dangerous a magical wish can be.
Donald and Goofy's differing views on Donald's I Just Want to Be Normal wish stems from their temperaments and relations to their family members. Donald is a Butt-Monkey par excellence bordering on Cosmic Plaything that is constantly caught up danger and dragged into adventures, which he desperately wants to avoid being part of, so it makes sense that he'd want a life where he can last three seconds without some kind of disaster falling on his head. Not to mention that Donald is in the minority about views on adventuring in the family, with everyone excited and eager for the next one while not always giving Donald the credit and respect he deserves. Goofy by contrast takes his own pratfalls in stride and sees his misadventures for the rare opportunities they are. And going by the pictures he has of his son, Max doesn't seem to have the same issues with his father that he did in A Goofy Movie or at least to a much lower extent.
Actually, the movie is CANON...this is post-character development Goofy!
When Goofy explains to Donald that each family is different, he’s also saying that despite how dysfunctional Pete’s family is, they still were a family and each had their own special way of showing how much they cared.
One nice touch. Sitcom Donald? Does NOT have the standard Donald Duck Freakouts, despite the fact that Don Cheadle can, in fact, do one. Instead? He has a more mundane 'deep breathing anxiety' issue...as Donald has a SERIOUS complex about his temper, to the point of going to therapy over it.
When Launchpad is about to play his song, it abruptly cuts to another scene, and when we finally cut back to him, it’s when the song is over. Gag aside, it can also be seen as Gene manipulating the “episode” to cut away from the band so he won’t have to listen to a long, cheesy song being blasted into his ear for two and a half minutes.
Collie Baba having two different lamps (the one from "The Treasure of the Found Lamp!" and the one in this episode) makes a bit more sense when you realize the original series also had two distinct genie lamps: the one from the episode "The Master of the Djinni" with a DogfaceJackass Genie and the one from DuckTales the Movie: Treasure of the Lost Lamp with a duck-faced Benevolent Genie named Gene. In D'jinn's flashback, his genie ancestor even looks a bit like the one from "The Master of the Djinni".
According to Donald, the previous "episode" was about Louie breaking Della's favorite vase and learning a lesson about honesty. Earlier, Louie made a remark about using Scrooge's bad example to excuse future lies. This was most likely Gene's way of preserving the status quo.
Goofy and Max being Real After All makes complete sense if you’ve been paying attention in previous episodes where we see various locations and elements from Goof Troop and A Goofy Movie, such as Spoonerville, Lesters Possum Park and Powerline.
One of Donald's photos shows the Quack Pack versions of him and the triplets getting attacked by a tyrannosaur and a pterosaur, despite living prehistoric creatures would be out of place in a mundane sitcom. However, given both archosaurs don't look realistic (in contrast to other non-sapient animals in this show), it's most likely they are not the real deal.
Fridge Horror
While the Ducks were trapped in the sitcom reality, what happened to the rest of the universe? Did it cease to exist? What would have happened if Donald never undid his wish?
Let's Get Dangerous revealed that every work of fiction is a peek into another dimension, so it's likely that the Quack Pack set was one of these other universes.
Gene offhandedly mentions that "it will probably be cancelled and rebooted". What if the show was permanently "cancelled"? It's shown that Huey was keenly aware when there was a scene change that he wasn't a part of; he at least knew what happened but he wasn't there. Would they simply cease to exist? Would Donald even be aware of this until it's too late?
If everyone from the cast exists in the "reboot" version, they'll just be magically turned into their reboot selves, with no memory of their earlier sitcom selves other than the uncanny ability to pull a Mythology Gag. Not sure how a permanent cancellation would work out...
Either the show could never get 'cancelled' since Gene was probably just joking...or that Gene would just kick them back to reality or restart it.
Supposing the show would be rebooted, that would be no better when you think about it:
First, how long would it take for that to happen? This reboot already had to wait 27 years after the original's end before being released. What if it took that time or even longer for the reboot to come out? And what would happen to the Ducks in the meantime?
Also, just like with these versions of characters like Webby, Beakley, and Huey, Dewey, & Louie, their rebooted selves may be In Name Only versions with little in common with their real selves, meaning that they could have lost their true identities, which is definitely a Fate Worse than Death.
And to make things worse, what if the reboot took a Darker and Edgier route? For this kind of show, that would mean that situations typical of sitcoms such as Amusing Injuries and family dramas would be played dead serious, which, if it also averted Negative Continuity, could most likely just split the family all over again, and possibly gave them more realistic traumatic experiences such as bullying with equally realistic consequences.
The show puts Goof Troop and Goofy Movie into the same continuity. That's cool and all, but there is also the implication that Peg finally got fed up with Pete's get-rich-quick schemes and divorced him, taking Pistol with her. She and Pistol are nowhere to be found in Goofy Movie.
Donald is able to remember the "previous episode". How many episodes have happened before the one where Huey figured out they were in a television show? How long have they been trapped in Donald's wish?
Fridge Tearjerker, actually: In one of Goofy's photos with his son Max, Goofy is shown holding baby Max's hand, and he, Goofy, appears to have a sad look in his eyes. Goofy's wife was already a Missing Mom in Goof Troop, but this photo seems to suggest that she met an even more tragic fate than the fans previously thought!
Assuming the show takes place anywhere from 2017 to 2020, this means they were born in the early 80s, and would have spent a sizeable chunk of their childhood and all or most of their adolescence in the 90s.