vgmrips

According to the in-game credits, the soundtrack to this version of Star Trader was composed by — in addition to Hatsushiba — Yasuo Ito and Takeshi Maruyama. I don’t remember Yonao working for M.N.M.

I can definitely see where you are coming from since Falcom Music Channel also supports those credits. However, Keishi Yonao has stated on his twitter that he did work on the game and it's also referenced on this spreadsheet. It's not uncommon for people to get miscredited or not credited at all, case-in-point Michiru Yamane was uncredited for King's Valley 2. It's undeniable that some of the songs in Star Trader X68k have his style, so unless any of the people originally credited come out and clarify then we could correct it.