I come to the VGMdb forums for stuff like this. I haven't even listened to Ys 4 very often and wasn't looking for a composer breakdown. But reading research like this is way more interesting than most else on the net.
I once thought about creating a website for VGM composer breakdowns meant for analyses like these. After solving several mysteries and gaining credibilty, composers and game companies might realize that we fans care about who composed what. Maybe some would even find the site themselves and help out, and not just respond to inquiries (if even that). Too bad I'm a lousy programmer and can never create my ideas for various VGM sites
