You were so close now.

Tense check! "were" —> "are"

Perhaps it was due to an unnaturally quiet approach or the turbulence of your own ever-darkening thoughts, but you failed to register the voice behind you. Or the set of hands shaking your shoulders. Or the… second?

I'm like 90% sure this should also be present tense, since it's a "here's what's happening now" kinda thing. Second person can be weird.
I'm gonna stop making note of tense because it's a bit funky throughout. I'd go back and comb for it, shift it to be consistent, one way or the other, past or present.

A rush of red warmth rises from your core, smacking you right across the cheeks.

Literally me when woman. This is second person, I get to choose where my mind goes!

WIth any luck it's related to the bump

Note to fix "WIth"

Rising to your feet you’re stuck with the awkward realization

I presume you meant "struck" instead of "stuck"? I think? I can rationalize how "stuck" works in this scenario, but I can't help but also think you possibly meant "struck".

You do your best to stammer out an apology, emphasizing that you didn’t mean to cause any offense.

I don't typically relate all that much to a second person "you," but by pure serendipity you've managed to really capture me here. I hate it.

One could cook a mighty big meal on the dead-pan expression Carmine was giving off.

Baller line. Genuinely.

And there's plenty of you I don’t know, And I’m so happy to meet you!

Note to lowercase the second "And".

However, I would ask each of you to consider why you’re here.”

“Looking for an interesting way to spend an afternoon is all well and good. But…

If you're gonna move on to another paragraph while still in the same quotation, you take out the closing quotation mark, like so:

However, I would ask each of you to consider why you’re here.

“Looking for an interesting way to spend an afternoon is all well and good. But…

You feel taught.

"taught" —> "taut"

But… as scary as they thought was, perhaps she was right.

"they" —> "the"

You observe a Librarian, head made of flowers exasperatedly pacing in front of a dense wicker sphere.

Toss a comma in after "flowers".

The fear of and uncertainty of being on your own.

I'd nix the first "of".

Launching the bamboo toys into the skys to dance with the lantern koi

"skys" —> "skies"

To answer your questions:

• I like the character interactions a lot, but I have to agree with kblacke, give us some more. I'll elaborate more on this in a bit, but it all goes by so fast.
• I think the hesitation is explained enough to give the general idea that the protag really messed up at some point. I think I'd like a bit more, especially when it comes to the survival part because what happened there?? I know you probably don't wanna give a ton and that's fine, but please can we have some more? Pretty please? With a cherry on top?
• I think the ending as is is fine enough, but, again, I just find myself wanting more of it all. Which leads into my big general crit…

I really like this piece, I think it has a ton going for it (it also helps that this is a second person that largely acts like I do which is a strange experience to be sure.) But I think it moves way, way to fast. I want you to marinate on everything, be willing to stew in the scenery and people. You've created an extremely chaotic setting and now you've gotta find a balance between that chaos and pacing. The million-miles-an-hour approach doesn't really work all that much, just leaves me feeling disoriented and overwhelmed. As I type that I can see how that might be intentional given the setting and second person, but I think I'd rather be engulfed in a gentle riptide than a tsunami, y'know? And this isn't just for the fair part only, the whole piece moves far too fast, but it only gets worse once the fair hits imo.

Also, I want more Dendra. Give me what I want, author! I say that in a jester's tone, but I really do mean it. She seems like a really interesting character with a seriously dense background of tomfoolery and misdemeanors, but there's something else there that you teased at but never got to. What happened when the protag agreed to go to the sign up? What was that all about? Is she aware of the protags misdeeds? Was she affected by them? I wanna know, and I want more Dendra generally! Also, "Dendra" is also super close to "Daedra" and I couldn't stop thinking of those spider-women from Oblivion. So there's that.

I'll also say that I'd suggest going through and taking a look at your sentences and where you end them. The thing has a very start-stop nature to it that makes it a bit awkward to read. I dunno if it was stylistic in nature though, which makes this an even more subjective crit. This thing has so many grains of salt for you to take it with that I think I need to call my doctor about my blood pressure.

Another note: I would encourage you to make the collapsible where the protag unfolds the paper be the flavortext. The "Open" and "Close" is kinda meh imo.

I also saw a few times where you surrounded a word with asterisks. I dunno if this was you trying to italicize them or a stylistic choice so I thought I'd make note of it just to be sure.

But to end this on another "I liked this" note: I really liked how integrated this was with the Library, how you pulled so many other things into it in a fun and interesting way. It's something I try to do with my own Library pieces because I think it's fun, and by transitive property I find it really fun to see in other pieces.

Keep up the good work and good luck!