Monika is pansexual, confirmed sooooo, cool =D

Sayori is a omnimantic demiromantic asexual, which is why she fell for Kenji from being friends with him for so long

Yuri is a bisexual, which is why she falls in love with Natsuki

Natsuki later discovers that she's actually a lesbian, and didn't really love Kenji is a romantic or sexual way, which is how she fell in love with Yuri eventually

Kenji is pansexual, he just vibes-