Looks like Saori has a thing for Haine and doesn't even know it.
She knows it, she just doesn't know WHO Haine is! (If she sees her with Ayaka and Yurine, she'll be likely to think Ayaka is the one who was playing the piano based on her preconceived notions... Though her hair isn't straight... Hopefully she'll get over the fact that Haine doesn't have black hair!)
I really don't see this arc heading toward polyamory, unlike the last arc. For one thing, there's that bit at the end that suggests Saori is probably going to end up with Haine... Also, look at the cover picture of Haine, Yurine, and Ayaka. Yurine is gazing adoringly into Ayaka's eyes, while Ayaka grasps her hand and looks like she is worried sick about her, gazing back at her. Meanwhile, Haine and Yurine's hands are resting on each other, not clasped, in a friendly manner in other words, while she looks toward the unknown (Saori's) hand reaching toward her from out of the frame.
There is also the fact that Ayaka and Yurine are 2nd year high school students while Haine and Saori are 2nd year middle school students. That is a three year difference. In ten years, that wouldn't be much of a difference, and I will admit, I dated a couple of girls who were that much younger than myself when I was in high school. (I was a senior and they were freshmen... well, one was right after I graduated, so I guess she was a sophomore and I was a recent graduate.) But you rarely if ever see that kind of age gap in manga. If there's an age gap, it is usually a serious age gap of five to ten years.
No, I think what Yurine needs is someone other than Ayaka who is actually a friend and someone who can bring out what she seriously lacks, which is the ability to care about anything that isn't Ayaka. Of course, the thing that kept going through my mind through the entire section when Haine was asking her if she ever felt passionate about anything was, "OF COURSE YOU HAVE! What about AYAKA!!!!!! But I guess that doesn't count, since it isn't something of a similar nature to playing the piano or gardening or sports. The other question that was going through my mind was, Isn't Ayaka exactly the same? She doesn't have anything she is passionate about other than being number 1, which is just academics. It isn't doing something for something's sake. And she's already been dealing with the fact that it is really about her mother and not herself anyway. So I wonder if Ayaka will have a bit of crisis while she helps Yurine through hers?