I really like the tracks you mentioned, too. Of course, I like the whole soundtrack, but whatever. "Cold Iron" also has a tendency to just about give me chills, too. You can hear the pain and strife boiling beneath the surface of the longing melodies. And the whole piece builds up to the end when the rug is pulled out from underneath it and it stops too early.
One that always leaves me a bit mystified is "Stride." I can never decide if it's quite happy or somehow melancholy. The melody begins on a bright note even though the chords in the piano seem pensive to me, but then the piece takes a somber turn rather quickly, and the bass line emphasizes this as it imitates the melody's gesture. The harmonies wind through cheery drones to perhaps foreboding chords on the piano. In the end, I think it's mostly an optimistic piece, but to me it encapsulates the nature of human relationships (which is what KS is all about) as well as any short piece like this could. Even to the point of having two of the main melody instruments, guitar and bells or something like that, which sometimes play separately, sometimes they join together in unison, and sometimes they play complementary melodies at the same time, almost like how people meet, join together with someone for a moment in time, then grow farther apart until maybe they come back together some later time and have a greater understanding of each themselves and each other and how they can better fit with that other person.
Oh, and also, there's a drum pattern that goes throughout "Stride" (3 even beats, followed by four beats where the first two are very close together) that sounds like certain heart arrhythmias. I wouldn't be too surprised if that was done on purpose.
I've only seen half of the cut scenes (Intro, Emi, and Rin), but you're right, they also have some great music. I just watched them again, and the Intro grabbed me with how ethereal it is, as if to suggest how distant Hisao became during his hospital stay, how disconnected he felt from reality or the outside world with nothing but his irregular heartbeat and the endless ticking of the clock to mark the days as they blur one into another. I'll definitely be keeping an ear open when I get to Shizune's cut scene, though, thanks for the heads up.
Am I reading too much into all this? Probably. But that's what I do. Oh well. Anyway, it looks like I still have about two tracks to unlock in the jukebox. How exciting.