yeah they are, but japan has a bit of a, how do i put this, thing when it comes to cousins, similar to how there are SOOO many depictions of brothers and sisters who are in love with each other across different manga and anime, it’s the same with cousins, it just seems to not be as taboo in japan for cousins, even first cousins, to be in a relationship, hell it’s still perfectly legal for first cousins to get married and have children in japan and there are more people than you think who are still doing so

Toono can have both yacchan and kashima. They're perfect for polyamourous relationship. They're all care for each other