A small hint that Bubba was the first in the line of clan McDuck? His first scene has him out hunting for treasure and being able to barely avoid the traps.
Bubba quickly adapts to the modern world instead of going full on Fish out of Temporal Water like all the other time-displaced subjects. A sign that he is indeed "smarter than the smarties" like Scrooge.
How can advanced sculptures, like the gem-eyed idol Louie steals, exist in prehistoric times when there are no civilized animal-people to make it? Let's not forget that this universe runs on an All Myths Are True logic, so the idol could have been crafted by gods, demons, aliens or other supernatural beings.
These supernatural beings would have existed since the Mesozoic or even the Paleozoic, hence why Louie would go far back to the Late Cretaceous for treasure (since a Triceratops ended up in the present).
Alternatively, Louie might have simply brought back dinosaur bones, which are also valuable.
After they get zapped back to the present, the Duck-McDuck family reappears in different outfits and positions that indicate what they were up to when the Time Tub zapped them back to the present.
Mrs. Beakley returns as a pirate, complete with tricorn hat. As she appears in a painting of Scrooge, Donald, and Della fighting Captain Peghook the Ghost Pirate and his crew, it's safe to say she landed in the middle of one of their pre-series adventures.
Scrooge is dressed like an Arab nobleman. His hands are positioned as though he were standing between two people and pushing them back away from one another. Scrooge maneuvered his way into wealthy status, and may have been in the middle of mediating a dispute between two other parties when the Time Tub warped him back. Word of God reveals he was T. E. Lawrence.
Dewey and Webby are dressed in late-'60s garb. Dewey is lying facedown on the floor, and Webby looks like she just jumped back in response to something falling in front of her. They landed in Woodstock. Dewey tried to crowd surf by jumping off a stage and having Webby catch him. Webby, not understanding what Dewey was doing, jumped back and left Dewey to faceplant.
Huey ended up in the Old West, and comes back wearing a cowboy hat and a pancho. The way he's seated when he appears suggests he was sitting on log by a campfire chatting up a gang of cowboys.
Launchpad is still in the clothes he left in, only dirtier, more disheveled, and sporting more patches. His tie and hat are both missing, and he is now wearing what appears to be a scarf or cowl. The setup looks like it's for a post-apocalyptic future a la Mad Max, but given that it's Launchpad, what he really saw remains to be shown to the audience.
Della shows up in full plate knight armor. Her armor is clean, she's standing up straight, and she does not appear to have any weapons, drawn or sheathed. She may have been standing before a king in ceremony when she was zapped back, and possibly about to receive an accolade into knighthood.
Why is there a Triceratops in Bubba's painting with Louie, Launchpad, and the Time Tub, before Tootsie actually shows up in the mansion? The painting represents Bubba's witness on Louie and Launchpad's time travels, and he might have already seen Tootsie appear in the present as a result of the two bringing back something from the Cretaceous period (Bubba has been established to be intelligent by cave-duck standards).
In Bubba's eyes, a Triceratops would be similar to the prehistoric rhinoceroses and bovines contemporary in his time, hence why he would ride one.
There's some clear Rule of Symbolism in Della coming back in Knight's armor. In order to fight for the right and do more for her reckless son, she has to wall herself off from his deflection and moaning and give him a true punishment. Kinda like how knights would do so idealistically.
Tootsie's Adaptational Villainy actually makes sense considering she's reimagined as a wild animal rather than a domesticated one, due to the fact non-avian dinosaurs did not live with humans. There's also the fact domestication also comes with a gene that turns the animal cute and docile.
Compare the arguments over whether Louie should or shouldn't have been punished to what actually happens in the next couple of episodes, and it becomes clear that neither of those options were 'right'. Louie was clearly getting out of control and needed consequences, but blind punishment often fails to have a positive effect on children, instead making them resentful and encouraging scheming to get around their parents. What Louie needed most was more supervision and guidance, plus a willingness to accept those things. Punishment alone does not make one a better parent.
At one point, Dewey uses the term "caveman" instead of "cave-duck". This would be a goof if it weren't for the fact "human" or "man" by this world's context is anthropomorphic animals, which includes ducks.
Della's initial reluctance to discipline her sons makes sense when you account for how she spent a decade trying to reunite with them and still only recently came back into their lives. Della was probably worried about doing anything that might push them away or cause them to shut her out.
Fridge Horror
When Louie passively-aggressively tells Della "I wonder who I got that from" when she tells him how irresponsible he was for using the Time Tub to try and get rich quick, it hints that he still hasn't totally forgiven his mother for technically abandoning him and his brothers when she took the Spear of Selene. He was the most skeptical when she finally returned to them, appeared to be the one the most hurt by Della's absence as seen in "The Secret(s) of Castle McDuck!", and hasn't warmed up to her the way Huey and Dewey had in their own episodes with their mom.
Try not to think about what Della fought through in her trip through time before getting returned to the present which sees her as a knight. Her own anger at Louie clearly indicates the experience was not pleasant for her at all, so it's quite hard to blame her for punishing him in such a manner. To be put through another hell like that can bring out the worst in anyone.
Tootsie was already that aggressive and dangerous as a young Triceratops. Now what would happen if she was brought to the present as an adult, with fully-developed horns...
Paleontologists now believe herbivorous dinosaurs, particularly Triceratops, would sometimes include smaller animals in their diets. Tootsie could be trying to eat the Ducks as well as acting out of territoriality.
Louie could have also accidentally brought back another dangerous animal during his visit to Late Cretaceous North America, such as a Tyrannosaurus rex.
Given Launchpad ended up in the end of the world, that lightning blast from the Timephoon can take the family to any point in time or history. Like World War II. Or the San Francisco earthquake. Or the eruption of Mount Vesuvius. Or the K-Pg extinction event. Or the P-Tr extinction event.
Launchpad tells Dewey about how he saw "how the world ends", then offhandedly mentions how he'll "see [them] there soon", meaning that the apocalypse will probably happen during the triplets' lifetime, possibly before they're even adults!
Then again, Launchpad is, well, Launchpad. Far as we know the world ending was some billion years into the future and the words just slipped out of his mouth like that.
