DaMemes here. This mod has custom music selected by yours truly. If you wish to have a listen to them yourself, do [/toggle-soundtrack on] to replace the vanilla tracks with custom tracks. You can choose to revert that action anytime by doing [/toggle-soundtrack off].
Anyways, here is the list of custom music that corresponds to each stage, alongside the author of each port.

(0x1) Star Catch: Jujutsu Kaisen - Ao no Sumika (port by Serium, fixed by Fearl when ported to coop)
(0x2) Course 2: Touhou 3: Phantasmagoria of Dim. Dream - Maniacal Princess (port by me)
(0x3) Course 3: Super Mario Galaxy 2 - Beta Song 3 (port by VanessaWolfe2015)
(0x4) Castle Main Floor: Touhou 16: Hidden Star in Four Seasons - A Pair of Divine Beasts (port by me)
(0x5) Course 7: Legend of Mana - Earth Painting (port by ???)
(0x6) Course 5: Touhou 19: Unfinished Dream of All Living Ghost - The World is Made in an Adorable Way (port by me)
(0x7) Final Bowser: Touhou 7.5: Immaterial and Missing Power - Oni's Island in the Fairyland ~ Missing Power (port by me)
(0x8) Course 6: Dr. Latency's Freak Report - The Childlike Duo's Naturalis Historia (port by me)
(0x9) Course 1: Neo-traditionalism of Japan - Wind of Agartha (port by me)
(0xB) Course 4 & Piranha's Lullaby: Touhou 11: Subterranean Animism - Walking the Streets of a Former Hell (port by me)
(0xC) Course 8: Mario & Luigi: Bowser's Inside Story - Grasslands, All the Way (port by Cryogeon, fixed by me when ported to coop)
(0xD) Star Select: Seinfeld - Main Theme (port by MilesGaming)
(0xE) Wing Cap, Vanish Cap and Koopa Shell: Touhou 4: Lotus Land Story - Dream Land (port by me)
(0xF) Metal Cap: Touhou 4: Lotus Land Story - Faint Dream ~ Inanimate Dream SC-88 Pro Ver. but with Metal Cap Instruments (port by me)
(0x11) BLJ Control: Touhou 2: Story of Eastern Wonderland - World of Empty Dreams (port by me)
(0x16) Stage Boss: Touhou 9: Phantasmagoria of Flower View - Ghostly Band ~ Phantom Ensemble (port by me, idea was from Touhoumon)
(0x17) Key Get: Fire Emblem Main Theme (port by Gael95)