Minori was never a tsundere and never showed signs of being a tsundere. She's just spoiled, but she's done nothing but fawn all over Youtarou from chapter 1. Of course he's not dense enough to miss that. Saionji is pretty dense though...she doesn't even understand sexual relationships. She needs someone to take care of her. Minori would be mostly fine on her own, it's obvious the only reason she's living with Youtarou is because she begged their 2 dads to set it up.
I'd love a future chapter where Youtarou's dad is fighting with his mom because he wants Youtarou to marry Minori and the mom wants him to marry Saionji. I wonder if Kaho will ever enter the harem, or the Class President.