Still working on it, but most of the songs from the game are either covers of songs from KOF '98 or Jim Croce songs:
Japan Team stage - Unknown
Art of Fighting stage - New York's Not My Home by Jim Croce
Boss Team stage - This was unknown for a long time and I almost thought it was original. Finally confirmed as These Dreams by Jim Croce.
Goenitz stage - MIGHT be It Doesn't Have To Be That Way by Jim Croce.
Iori Team stage - KOF '98 - Art of Fight
Unused Track 1: KOF '98 - In Spite of One's Age
Unused Track 2: Unknown
Unused Track 3: KOF '96/'98 - Esaka?
Thus three tracks are still unknown.
Okay, I solved another one today. Goenitz' stage is actually "Fanatic Waltz" from KOF 98, aka Orochi Shermie's theme. This song was corrupted almost beyond recognition, and I only recognized it by accident.
Now only unused track 2 and the Japan Team stage need to be identified.