Some time ago I found
a blog with scans from the Japanese booklet for Pokémon Pinball with full credits, and the exact sound credits that figure there are as follows:
Music (おんがく)
Go Ichinose (いちのせ ごう)
Sound Effects (こうかおん)
Morikazu Aoki (あおき もりかず)
Sound Driver (サウンドドライバー)
Tetsuya Watanabe (わたなべ てつや)
Sound Direction (サウンド ディレクション)
Junichi Masuda (ますだ じゅんいち)