From my memory, I believe Happy NEET was also second cousins.
I think these are going to be my guidelines on incest from now on:
1). Second Cousins are the MAXIMUM closeness in relationship that I'm going to be fine with
2). They have to have not been interacting with each other for a majority of their life (no actual familial bonds, basically- if you grew up together as a family or something then that's a hell no..)
3). Has to not be a major plot point, if the game is like, making a HUGE deal out of them being somewhat related, thats too far into making incest a kink.
With that being said, I'm probably going to finish Akira points as it (to my knowledge) just about fits all of the points i just made, and I don't want to drop an otherwise amazing game for something I can ignore/could've just not seen (like happy neet)