The Silver Case Demo (PC Version; .FSB .mid?) by AceK at 6:14 PM EDT on August 9, 2016
The game appears to run under Unity. There are some .mid files intact in the game along with .FSB files (including SEQPlayer related information). Outside of that, .OGM videos are used for video playback.
.FSB convert/view options seem to be the stopping point for me, as I can't figure out how to proceed. Only clue I received is that it might involve the use of Vorbis codec. FMOD Studio can open it, but playback is not possible (nor is FSB creation... since only FMOD Designer seems to support this, and I have no luck in finding a mirror for it). I also don't have the tools/knowledge necessary to "compile" the FSB Vorbis Extractor (Github Link of fsb-vorbis-extractor)
I think the general bgm is really only played in the .FSB files themselves, and the .mid tracks and seq player bits were there to test the possibility for any use in-game.
I see... then yea, it looks like they have ditched the possibility of sequence playback.
Did you managed to check every .FSB track along the way? I think it was publicly said that some tracks are remixed, but not everything will be according to Cheru.
EDIT: Here it is... it actually sounds like the OST should be the same as the PS1 version, but with remixed tracks included: