All PoFV tracks were supposed to have MIDI versions
The trial version of Phantasmagoria of Flower View has MIDI soundtrack. But these files are available even in the full version. By renaming thbgm.dat to something else and deleting the .cfg file, you can listen to the MIDI songs in the full version. However, only the songs that were in the trial have MIDIs in the full.
If you extract the files from the full version, you will find the MIDIs. You can see that there are only 7 tracks available to listen to.
The musiccmt.txt file contains the music commentaries of the tracks and their corresponding .mid files. In the trial version, you will find the commentaries only for the 7 tracks. But in the full version, you can find the commentaries and the corresponding .mid files for all tracks.
Even though ZUN didn’t include them all in the full version, you can see what the files would have been named.
This is the proof that, at some point, all tracks were supposed to have a .mid version as well.
花映塚 ~ Higan Retour th09_00.mid
オリエンタルダークフライト th09_00b.mid
春色小径 ~ Colorful Path th09_01.mid
もう歌しか聞こえない ~ Flower Mix th09_07.mid
風神少女 (Short Version) th09_08_2.mid
彼岸帰航 ~ Riverside View th09_09.mid
六十年目の東方裁判 ~ Fate of Sixty Years th09_11.mid
ポイズンボディ ~ Forsaken Doll th09_12.mid
今昔幻想郷 ~ Flower Land th09_13.mid
魂の花 ~ Another Dream... th09_17.mid
幽霊楽団 ~ Phantom Ensemble th07_09.mid
東方妖々夢 ~ Ancient Temple th07_10_b.mid
狂気の瞳 ~ Invisible Full Moon th08_12.mid
It’s interesting that some of them have th07 and th08 in their names. Probably they would have been the same versions from Perfect Cherry Blossom and Imperishable Night, although 東方妖々夢 ~ Ancient Temple is th07_10.mid in Perfect Cherry Blossom (it doesn’t have the additional _b in its name).