[CHz]

Some specific composer info for Gaiapolis was added to the 2ch best VGM contest wiki by a user named "technouchi," which could be Yuji Takenouchi (I tried asking him on Twitter if it was but he didn't reply): [1] [2] [3]

Seiichi Fukami: 1.28
Yuji Takenouchi: 1.34

There are also some additional credits added by an anonymous user that may or may not be the same person: [1]

Seiichi Fukami: 1.01~8, 1.10, 1.12, 1.13, 1.15~21, 1.26, 1.27, 1.31 (KING DARKNESS), 1.32
Satoko Miyawaki: 1.14, 1.25, 1.36
Yuji Takenouchi: 1.31 (INVASION)

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There's also a full breakdown for Mystic Warriors added by "technouchi": [1]

Junya Nakano, Yuji Takenouchi: 2.23, 2.38 (Nakano - A melody & "hook", Takenouchi - B melody)
Yuji Takenouchi: 2.24, 2.25, 2.28, 2.29, 2.32~34, 2.37, 2.39~41
Junya Nakano: 2.26, 2.27, 2.30, 2.31, 2.35, 2.42~45
outsourcer (presumably 井筒屋夢之介): 2.36, 2.46