Shuichi Kobori is actually 小堀修一.
http://www.konami.jp/kojima_pro/twohan/02.html
You can see Kazuma Jinnouchi's kanji name in the arrangement credits (陣内一真). Still working on the other two.
There are actually two prominent people who share the name 戸田信子, this is the
wikipedia article for the composer (the other is a newscaster).