After reading what you've all wrote, I've come to conclusion that you all thought as readers and critics, not storytellers. You all didn't go deep and didn't ask the underlying question behind those questions, "the fuck 'plot' and 'driven' even means?"
Plot, or narrative, or story, or coherently mashed words together making sense, is a chain of sentences that make a causal structure that affects the reader over time. It affects the reader right now, and builds context over time. If you read the previous thread, where I explain CCC, "plot" is essentially Context + Character from authorial side.
Little refresher, context is a things that happened before that reader knows and the context that is unknown at the current moment. Everything from worldbuilding, character descriptions and their actions that happened before, and the things that reader saw but doesn't know, that you, as an author know it, even if you're BS-ing your way through the story. Character, are narrative agents that do things RIGHT NOW, changing status quo, revealing the unknown context into known, and affecting the reader right now. If you're smart, you already see where this is going. If not, buckle up.
Plot, therefore, is the result of a change that happened RIGHT NOW, through something that's important to the author AND the reader. That important thing is whatever you, as a storyteller is fixated upon, be it MC, your world, the voice inside your head, and you want the reader to know about it.
So, we know what plot now is, I can answer what "driven" means. Driven, is the past participle of drive, used only in perfect tenses. Bruh. Drive, from multiple definitions, has this one: "propel or carry along by force in a specified direction". This is what "-driven" means, to use either "character" or "plot" to carry the "story" is a certain direction. But what is an engine that "propels" the story? Description. Bruh.
As far as I read no one had commented what makes something driven besides vaguely deep something that is either focused on MC or the events that happen. Sure, that's a valid read... from analysis point. This kind of "-driven" explanation happens only after you digested the story and thinking, "what the hell I just read?", and then the mind rationalizing that X plot had a lot of focus on the characters, therefore it's "character driven", or Y plot had a lot of focus on the world, overlaying context therefore it's "plot driven". But, other reader can see X plot as a plot-driven, because it was focused on characters solving and interacting with the plot ponts a lot, and Y as a character-driven because despite plot points happening, it was centered on the characters realizing the meaning of the causal events that happened.
I'll answer the last half of Question 3 right now. Analysis is subjective. Reader is subjective. Many readers, in fact, from different backgrounds and reading capabilities, therefore is downright unpredictably predictable due to probability distribution. Yes, statistics are included in subjectivity. That's how proper analysis works, finding objective, most agreed upon logic, aka "informal agreement" and attempting to make something everyone can agree at least more than half points.
But how this helps to explain the "drive" of the story, you may ask, and I'll say it again, description. That external and internal description two threads before. Internal description is subjective, be it thoughts, emotions, something that happens inside the story characters. External is objective, the world itself, the actions the characters make, and just plain logic. As I described before, you can't separate one kind of description from other, and they'll mix even if you don't want to. Without external, there's no movement, without internal there's no substance to comprehend
Therefore proposition is thus:
From authorial side, there are no drivers. There's only yours, authorial. Authorial drive, authorial intent in other words, is what makes the story to have an engine. YOU ARE THE DRIVER.
You are the force. You, the author. Your descriptions, your emphasis, your stylistic choices, your withholding of info, your reveal of emotions, your ironic asides, your POV character’s thoughts about admiring Ug for his wheel making skills.
Plot-driven vs. character-driven is not about what you think happened. It’s about what the author, the storyteller, YOU, for fuck's sake, emphasized through description in real time. That's the reader's job to decide was your storg plot-driven or character-driven. You, as an author is a reader of your own story too, so you have opinions about it too.
So, taking that assumption, let's say you wanted character-driven story about hero killing the demon king. You do that well, or at least think so, and explored the inner world of the hero to the fullest, made him to face hard questions, et cetera, that makes full use of internal thoughts. But, majority of other readers says it's plot-driven, because everything is about stopping demon king, and nothing mattered from these hard questions, just more battles and choices. If your intent is misaligned with what your readers say, you've failed at making the plot-driven or character-driven story. The failure is that simple.
So, your question here must be "what to do to not fail?", and I'll say that it again, description. Your choice, your intent in writing the description, i.e. every sentence, every word, down to the single letter makes a difference. Every sensible storyteller who revised a scene or sentence at least once knows this, even unconsciously. How you deliver story is how the readers will read, and how readers will read will shape their verdict, regardless of your own intent.
Intent must be seen properly. Clarity is what makes the intent be seen, and that clarity is in how you describe things to the reader. As I said, most readers agree about most things most of the time, and your job with intent is to be curate the reading experience for readers to see what you really meant, to say "ah, yes, this is a character-driven story because hero had internal journey while travelling to the demon king, and the demon king is a subtext for the hero's childhood trauma being overcome through the loyal friends that followed him on the journey". Even if that demon king subtext was misread (you just wrote that scene because it was cool), the message, the intent you, as a storyteller delivered is seen well enough for everyone to understand what kind of a story this is. Outliers will be there always, you need to connect with people who understood and liked your story most.
As I always say, storytelling is communication of ideas. You can slap any ideas together however you want, but if nothing drove the story, it fails to be a story altogether. There in fact could be different story drivers, but that's the subsection of an authorial intent. Examples: Black Mirror, theme driven, about "what if"-s, and horrors of the systems that are created. Wikipedia article, explanation driven, about "objective" (not, because using second hand sources of those "journalists" is an informational crime) view of whatever you needed. Philosophy, framework-driven, about trying to explain whatever the philosopher was obsessed with in a coherent, yet subjective way.
These all stem from one thing, author channeling their intent with clarity, experience and emotions, or inner authorial CCC, for reader to read that with their own CCC. Because they're subsection of authorial intent, unless author specifically said that it's "theme driven", no one will read through that. They'll say it's either character-driven or plot-driven, because that's how brain works when interpreting external/internal description laid down over time.
To recap, there is no character or plot driven story from authorial side. There's only authorial intent. How that intent is interpreted, however, creates that distinction due to external and internal description use, which one was more prominent over time, condensed after the story happened. There's only one driver, you, and how you channel that intent, through characters, through world, through the descriptions, makes the story propel forward. While subjective analysis is great, you need to know why this happens during writing, or your intent will be misread and you'll get unjustified hate because you miscommunicated. Know yourself and your reader, and you'll never be misread by your reader unconsciously.
And, while creation is divine, persuasion is survival. Amen.
