User blog comment:B214/Question & Answers 5/@comment-67.211.8.20-20150507180948/@comment-24502975-20150507221206

If Yasaka can flirt with the guy she knows her daughter will end up with, there's no shame in sisters sharing him.

She's already started to fall for him and will get her own volume in the future so she's definitely gonna be a part of the harem. As for her species, they always mate with males from other species so their bloodline doesn't have to be pure I guess, just pass down the Nekoshou's abilities since they're so rare.