Naofumi Hataya and Masafumi Ogata were also people we'd wanted to ask music related questions to, though I personally think that should be a lower priority than possible artists. Hiroyuki Kawaguchi/Hiroe would be very helpful person if they could be found/contacted and were willing to answer questions, as he was the art director. https://segaretro.org/Hiroyuki_Kawaguchi Yamaguchi/Judy has been on twitter and answered questions before. He was responsible for Special Stage Designs and could clarify that timeline a bit. https://sonic.fandom.com/wiki/Yasushi_Yamaguchi Hoshino is still actively working on the brand and has a twitter. Designer of Amy and Metal. https://sonic.fandom.com/wiki/Kazuyuki_Hoshino https://sonic.fandom.com/wiki/Sonic_the_Hedgehog_CD/Staff There are others, but those are some of the most visible options. Edit: And if you're willing to do it BlueSkies, you may be in a better position to do it than many of us here. Especially since we want any requests to be as professional and as friendly/respectful as possible.