SEILAH's real name is Mihoko Ando, apparently. Takafumi Miura said she was the original keyboardist in Gamadelic, but she got married and then quit the band/company. He did only say he remembered her surname, but I found an Mihoko Ando in a Data East game (
Dark Seal II), and almost everybody else is under their full name, so yea. (Edit: Her name was confirmed)
And speaking of Takafumi Miura, he only did SFX for Data East. No music.
I'm still trying to figure out who "
Chongue" and "
Arma" as well. Miura said he doesn't remember Chongue's name, even though they worked on the same game together. So I doubt this was a major member of Gamadelic because of this.
EDIT: Taihei Sato was asked about "Arma" and replied "May be support staff of sound designer.short term part timer.I forgot her name...". So Arma was a one time female sound designer, hmm.