I discovered these songs on the Scythian Lamb soundtrack and am pretty curious about them.
See the above link --the songs I'm interested in are all named "Band Take #"
What genre do these songs fall into?
It's Japanese Indie music. As per this quote:
A collaborative project initiated by session musician and long standing member of the Japanese indie scene, Ken Takehisa. With 11 musicians taking part, the artist sent recordings of not just melodies and chords, but also scrapes, noise and amplifier feedback for everyone to break apart use as the building blocks for the album.