I don't remember what source I used for artist info four years ago, but whatever it was credited Go Tsukada for acoustic guitar performance on tracks 22 and 25. Checking the scans, though, he's
not listed in the performance credits, so I've removed him for now.
EDIT: The Jin no Shou album for this game might explain the Tsukada credit, but we don't have scans for verification:
http://vgmdb.net/album/5192.