>I don't see the issue with the "whole school is gay" thing

This kind of instantly null and voids anything you say, but I'll respond anyway. This is an entirely unrealistic and clichéd trope, and the fact you think it's okay shows just how much your perception is influenced by the medium itself.
>You can't bring in ad populum just on the basis of, "well about nine girls went crazy about her, so the whole school must be."

Okay. A few things. That's not how you use the phrase 'ad populum'. Omnia dicta fortiora si dicta Latina is only true when you use it right. Also the whole "everybody is gay" statement is not to be literally, it's saying that all characters introduced are gay. And this is exactly the case where both with background characters, implied characters, and named ones. It's kind of ironic you say "How that's difficult to process is beyond me." in your very next line, but missed something as simple as this.
>Just because they cry, that doesn't mean their love is as deep as they say it is. That's not bad writing, it's just being realistic.

This is dead wrong. Strong emotional response directly means strong emotions. That's basic physiology.
http://en.wikipedia.org/wiki/Emotion#Neurocircuitry
==Slightly less related, but helps prove my point http://en.wikipedia.org/wiki/Measures_of_conditioned_emotional_response==
>The confessions aren't taken seriously, likely because the girls DON'T KNOW HER. You wouldn't accept a confession from someone who knew nothing about you (and vice versa) other than your name and face, would you?

I'm not sure why you think this is relevant. It is no way disproves my point about the contradiction. Even if the girls don't actually know her that does not change the severity of their feelings. The girls themselves are under the notion that the feelings are real and serious, so they are.

>They also keep saying "boyfriend". This is a HUGE hint that they aren't in it out of genuine feelings
>Miu, being the one closest to her, obviously should lose this thinking if and when she falls for her (if she hasn't already).

Yeah... I must thank you for giving an opportunity to point out even more bad writing.
We already know Miu's feelings are 'genuine', that was obvious as of the last page of chapter one. And on the very same page she also refers to Fujiwara as a prince. So why should we consider her feelings more serious that other peoples'? Because she's a main character? Not really a valid reason.