Howard Drossin
From Sega Retro
There's one key line from the 2008 SageXPO interview that explains how much of the S&K themes are Drossin's.
"The music was composed separately and input for the genesis by someone named Setsu (I think). didn't do any sound efx for Sonic 3." - Drossin
When combined with a part of the 2009 Gamasutra interview...
"1993...That same year I did my own album of Sonic music called Virtual Sonic, which did not get released until three years later." - Drossin
It means that all five songs done for the game were handled/ported/arranged by Setsumaru. In terms of the tracks' origins, Drossin never actually worked on any part of S3&K. The tracks were just slated to be used but weren't for Sonic 3 (where he's given a Sound Special Thanks credit) but were in S&K and S3&K (where he's given a Music Composer credit [just for those tracks]). - E102 (08/06/2011)