Number 7 is
Tomoya Tomita! Confirmed in this
interview with Good Feel developers. By the way, he is the composer of Wario Land: Shake It!.
And actually I noticed that Saiko Miki is a woman. In the Pop'n TWINBEE GRAFFITI's
booklet she is credit as Saikoro Tsumiki (the sixth name of the list), like CHz
transcribed.