@Lilliwyt—
I again read through all the previous chapters, including the chapters of
Hanjuku Joshi.
You might be right about the business of Youko with Ayumi. On the other hand, I feel as if many authors of same-sex love stories treat those of the
other sex (whichever that might be) as lesser beings, whose feelings can be discounted if not disregarded altogether. Consider the way that Ran, Mari, Shiori and thus Morishima discounted Tsutsui in
Chapter 14 of Hanjuku Joshi. Now, that discounting is by no means a good thing, but I think that the dynamic between Youko and Ayumi should be understood within it. I don't think that Morishima sees Youko as a bitch; I think that Morishima sees Youko as a character who is insufficiently accepting of and adjusted to her desire for Ayumi.
Consider that, otherwise, Ayumi will probably end-up unpaired, though Morishima clearly presents Ayumi sympathetically.
(Well, there's also the slim, loopy possibility that Yae and Chitose will each end-up with her first love.)