I feel like I've been missing something for the past 20 chapters. Both the comments and the editor notes make Touko seem sinister, but isn't she just normal? Like, with her dad she's a little clingy and cloying, but that could just be her trying to make sure he feels welcomed into her family.
With her friends, wasn't she taking the actions that a good person would take? I.e. maybe she doesn't really personally care for this girl who's obsessed with her, but she knows a good person would help her out and not want her to be ostracized.
If anyone at all is scheming, it would be the mom I think - in which case Touko's mannerisms are learned and probably not an indication that she's also being conniving.
I feel like when I read this manga, it's a social experiment by the author to see if he can convince us a character is evil using only how he frames her in panels, editors notes, and the absence of an internal monologue.
The last time she did anything sinister was with the bully.