I found the character interactions really fun, and I really liked the meta ideas.

“However, Charlie twisted on the ladder to face him . . .”
I immediately thought to myself, “Ohoho, is that my partner I hear behindst me, mayhaps I TWIMST aroumd and take an peep for mineself”

. . . I’m so sorry. Anyway, mission was definitely a fun read! I’m . . . still a little unsure about the vibes of writing what’s essentially a “spitefic” about another boarder’s spin-off, but it’s also true that you’re largely representing the writing quirks of Tawaki’s writing style accurately, so I can’t really argue this isn’t “honest criticism,” can I? And I did love how you animated Melpomene to be so unnervingly wooden and blank, contrasting her “talking head” dialogue with Jiwon and Charlie’s more fluid presence on the page. (Like, watch clips of how Cats gets performed, even in the film adaptation, and think how expressive and funny a Cats agent should be!
The humanoid cat lounged in the doorway, placing both hands on one side of the frame and bending her knees in a long stretch. “Behold, friends,” she said loudly, with a smile, “It is I: Propipants, the flapper cat! I love great big parties! I’m so friendly and outgoing, you could almost forget my culture is a super-weird death cult, with a confused idea of an afterlife based on overhearing humans speaking!” She pulled back up to a standing position, holding her hands curled up in front of her face and pouting. “I’m very sorry they brought me here from August 1929, because it’s been such a good year, and I’m certain the next decade was going to be even better for carefree parties and economic freedom!” She quirked her head cutely.
. . . This was a very long parenthetical aside, sorry.) And honestly, I feel a bit bad for Melpomene, too? Her outdated mindset, plus her experience with Big Brother during the Key to canon arc (great job, Spirit of Imagination!) have left her with such a hostile, antagonistic attitude, not just towards potential goodfic characters, but even against her own fellow agents if they don’t agree with her. It’s rather sad, to be so self-isolating in a setting as diverse as the PPC is!

You did a good job of showing off the fic; it really does sound like a lovely read, and a lovely alternate timeline for Harry! It stands in contrast to Melpomene’s insistence that any change from canon is automatically disrespectful, because what could be more respectful to Harry than giving him less bullying and more books? The kid deserves a little fluff now and then, even if the original version never knows about it, yeah? The joke about Harry getting into Ravenclaw’s dorm by shocking the door into asking an easily answered question was funny, and I like the mental image of the Ravenclaw students waking up to a dragon hoard of books! But I especially loved the final acknowledgement you gave the fic, repeating its title in your prose to reaffirm the fact that it really is okay.

I like the gag with the skeletons, too. The previous residents of the RC had some . . . secrets, did they? And the fact the skeletons “clock out” by just collapsing on the spot back into unlife is pretty funny.

New word you taught me: “syllogism,” though I’m not entirely certain I get it properly . . .

And typos:
Charlie snatched it out of the air and slammed into the wall.
“slammed it into the wall,” right now it sounds like Charlie hurt themself.

He walked over, but before he could get there, it burst open with a resounding bang.
I guess it’s pretty obvious that the door is what’s bursting open, but it’s been a couple paragraphs since you actually mentioned the door knocking, so I personally would specify the door in this line, Might just be a “me thing.”

The agents soon followed Dragon-Harry back to the Privet Drive as school ended.
I don’t think that “the” is necessary, unless this is a “British thing.”

Melpomene once again pronounced the misspellings perfectly.
I might have just missed it in my reading, but I feel like this is the first time Melpomene has pronounced a misspelling in this story?

. . . doesn’t wizard media also obsess over the ‘Boy-Who-Lived’ thing
“Does he truly,” said Melpomene . . .
I may be misreading here (there’s a paragraph in between that interrupts the dialogue), but if Melpomene is responding to Jiwon’s assertion about the wizard media, I think she should say, “Do they truly?” rather than “Does he?” But again, I may be confusing what she’s responding to here.

—doctorlit has been pronouncing “Melpomene” wrong! I’ve always assumed Tawaki had made the name up to sound like it would fit alongside “Bombalurina” and “Macavity” and the like, but I noticed while typing out this comment in Microsoft Word, that the name wasn’t getting the red underline beneath it. A search online turned up that “Melpomene” is one of the Muses from Greek myth, specifically the Muse of tragedy, who sang ". . . songs of mourning for people of note after they die . . .". That really is a 10/10 reference on Tawaki’s part; it links Agent Melpomene’s origin canon, with the cats selecting one of their number to enter the Heaviside Layer, and her current occupation as an assassin. (I know she’s DTO, but you know what I mean. She killin’ stuff.) Anyway, my point is, I’ve been pronouncing her name MEL-po-MEEN all the years, but it looks like it’s actually MEL-po-MAY-nee.