These 2 musicians wrote on Twitter that they participated in recording of most songs in Bintage :
Bass - the guys' longtime backup bassist MATSU :
All songs except track 7 Free! Free!
https://x.com/Matsu19800728/status/1816277648483705061
Drums - Hibiki (Matenrou Opera)
All songs except track 3 Bintage
https://x.com/HibikiShiraishi/status...68109561978888