That uniform looks really nice on Kobato, I don't doubt that both Kirino and Kuroneko would love to have her as their little sister.

Great, now I'm imagining a yuri threesome doujin of Kirino and Kuroneko having their way with Kobato while trying to get her to tell them who does it best.

Why would Kuroneko want to have Kobato as an imouto if she already has two?
She never expressed to have the same fetishes than Kirino.

I think (s)he's referring to the fact that both Kobato and Kuroneko have an obsession with a gothic lolita character.
Any degree of likeness can be used to pair up 2 characters.

I can't let anyone have their way with my Kobato.

Damn lol. Kobato just can't get a break huh? ._.;