I really like how this version of the manga feels more grounded than the other version, which felt more rosy.
Case on point: Shimamura's thoughts during the bowling outing. The other manga made it sound like she was enjoying being a harem protag while this version just straight-out mentioned...
The conclusion that he'd still consider her "family" with or without the romance is an amazing loophole to exploit against both the dad and the publisher lmfaoooo
Ggwp author-sensei
So to sum it up:
Dad still doesn't know what to do or how he feels and could never come up with a lasting assertive response,
Kii-chan may well never actually had feelings for the Dad and was only using him as her escapade,
Mii-chan still couldn't move on from her mom's death and would rage...
… knowing the tone of the manga, she wouldn't have a (strong) romantic interest towards Izumi, but Shikimori would be jealous no less. She might start a medium-length Shikimori jealousy arc. Both Izumi and Shikimori are new to this, after all.
The proper form is "I couldn't care less." If it's too confusing for you, let's translate it to modern tongue: "I have no more fucks left to give." The idea of the phrase is that all the 'care' (fucks) you have is all run out.
That said, damn Sensei, you done fucked up.