Plot hole: There is no reason at all why, being targeted by a few arrows by unseen enemies - a fire suppressed already by the salvo of their own archers - the Rourans would turn around their heavy siege equipment, away from the bulk of the enemy forces, and fire it, hurling a single heavy stone to the middle of nowhere when they have the whole rest of the army who could storm the rock the supposed enemy commandos hide behind, or the archers who could keep shooting - again, they proved to be completely successful. It also makes no sense that the all-powerful witch who made the warriors flee managed to do any of this, 'sneaking' by horse in the middle of the steppe.
Suggested correction: Mulan used the helmets of the fallen warriors to make it appear that a large force has flanked Rourans. Rourans didn't expect this new "force" and knew nothing about it. They didn't know its size. And while their original target seemed harmless, this new "force" was killing Rourans. Fear and death were the reasons. What you see in this scene is an enactment of one of Sun Tzu's famous quotes: "All warfare is based on deception. [...] Attack him where he is unprepared, appear where you are not expected."
What we see in the scene is laughable, and not because of the idea, which surely is based on the profound strategic motto you mentioned and we find in many folkloric tales in other cultures as well; what we actually see in the movie, is that she grabbed a couple helmets lining them up on a rock, and she shot a few arrows. Then she stops shooting, and we see helmets knocked down in their full view. The movie truly surpassed itself in showing it in the most phony way; had they shown her shooting from behind the rock responding to their fire, or the helmets not falling, or them just shooting at mist, terrified, it would have maybe worked. It's an enormous overreaction. That and, under no circumstance trebuchets are used that way anyway. And she did all this setup unseen, again.
In response to death, nothing is an enormous overreaction. Something or someone was killing them. They wanted to kill it, and they didn't have time for Facebook's famous brand of pseudo-myth-busting. What if they knew it was one girl shooting at them? They'd still have done the same. Being killed is a very personal matter.
Continuity mistake: At the arena, when Scooby's blue suit bursts, the ground is covered in small blue pieces that disappear in the following shots.
Other mistake: In The Croods, Guy was handing out bananas and gave one to Grug, which he threw away. But in this film, he does everything to get this mystical fruit that he hasn't had since his childhood.
Continuity mistake: Tim is showing the Nanny's phone to the others. He plays the message from his parents, but does it tapping the bottom part of the touchscreen, while the media file and its "play" button as established in previous views, is at the top. Likewise, when he turns towards Jane asking "Do you want to be taken care of?" he is pointing at the bottom of the device, but in the reverse shot his finger is at the top. (00:43:30)
Revealing mistake: During the dance number in the airport, Santa grabs a security guard who then starts break dancing. It's obvious this dancer is a stunt double as he's younger and skinnier than the real guard.
Continuity mistake: Look at the forehead of the hotel manager. Everytime he raises his eyebrows, you can see his prosthetic forehead piece.
Factual error: When John Thornton is in the bar, Hal comes up and punches him in the face. They fight and argue, and Thornton proceeds to say that Hal "sucker punched" him. However, the term sucker punch was first known to be used in 1926 while Call of the Wild was published in 1903. The story itself took place in the 1890s.
Other mistake: Dolittle starts with a voiceover narrative explaining how Dr Dolittle was deeply in love with a beautiful woman called Lily. On an ocean voyage Lily disappeared and was presumed dead. Dr Dolittle never got over Lily's loss. As a child I recall reading all of Hugh Lofting's Dr Dolittle books (now generally castigated for political incorrectness) and I am 100% certain that Dr Dolittle was unmarried, and never once had the slightest romantic inclinations towards any woman.
Deliberate mistake: In the Spanish release, the name of the family store is written in Spanish, but inside the place it's in English everywhere. This is a very common mistake in foreign kids' films released in Spain.
Continuity mistake: The kids are in the car with their dad, and despite the best efforts from the youngest, they are reached by his teacher. As the dad starts the "You were killing us" joke, his hand is on/off the steering wheel between shots more than once. (00:07:15)
Audio problem: When Peter is sitting next to Grandpa in front of the fireplace, he has several consecutive lines when he's seemingly reading off a cue card, and his mouth movements (or lack thereof) do not match the audio. (01:25:00 - 01:25:21)
Continuity mistake: Jane Curtin is teaching to a rather seasoned class. One of those old hags says sarcastically "Because we really never do anything." As she says it, notice Eleanor turning towards her momentarily. She then turns completely, facing the opposite way, but at the cut she is repeating the turn from the beginning. Moreover, Moira's mouth closes after she says "Enough!" but the following shot on Curtin shows her still jaw-dropped. (00:04:05)
Revealing mistake: The nefarious villain has just revealed to Prince Charming that he has kidnapped the princess, and shows her to the crowd as a big burly smurfy monster is holding her. The crowd in unison gasps and looks horrified...except an extra who just can't keep a straight face. (00:07:35)
Continuity mistake: While sitting on the couch, Peter suddenly has a clump of hair sticking up near the back of his left-sided part that disappears but reappears after some camera shifts. (00:01:20 - 00:01:42)
Other mistake: In the scene with a leak in the kitchen, the woman fixes it by turning an isolating tap above the leak. However the water would have been travelling up the pipe to the kitchen tap and so that wouldn't have stopped the leak. (00:34:00)
Factual error: Real-life Martina Franca is a town in Puglia, at the "heel of the Italian boot." The town shown in the film is the famous San Gimignano in Tuscany. And when Holly "defects" in order to go to the Hill of Tara, her departure point, as seen on Foaly's observation monitor, is the real-life location of San Gimignano. (00:35:50)