Along with the callback to what started it all in the first chapter (which also includes Nazuna inadvertently mostly repeating what she did that chapter), you know shit's getting real when there's nobody saying the title of the chapter. And this specific setting is already close to the scenery of the opening spread of the first chapter, so I'm getting close to seeing if my crackpot theory about this entire story being a flashback will be vindicated.
I've also ruined myself-- I now read the Viz adaptation and this one side-by-side with the raws when I can. The source I use for raws is behind by two chapters, and what's behind this entry's "Official Raw" link is behind by one chapter, so I can't compare with the raws at the moment.
That said, in this chapter, I think the two renderings are on pretty even footing (I'm going to tentatively conclude that 1) the Viz adaptation obscures Kou's sense of guilt on p.3 as a "feeling weird", and 2) the Viz adaptation washes out that Kou was about to admit that he fell in love with Nazuna, prompting a kind of typical reaction from her to "love stuff").
The context of 2) all but demands that Kou is trying to inch towards claiming that he's come to properly love Nazuna, but it's practically Kou stammering in a meandering way: 「でも俺…もしかしたら…もう…ナズ 」/"But I... maybe... already... Nazu--" (Nazuna interrupts him), but I think there's no obligation to make that assumption without Kou actually dropping the word or at least blushing.
1) is a clearer miss-- I think I can vaguely grasp the calculus involved in thinking that "feeling weird" is sufficiently equivalent to "feeling guilty", and if you look hard enough you can find some dictionaries that give "uneasy" as a secondary meaning (possibly to distinguish it from the legal sense of guilt), but there's nothing that gives legitimacy to understanding うしろめたい according to that secondary meaning (in contrast, it makes sense to lie about something you feel guilty about), and "weird" is nonetheless much vaguer and off the mark than either of these.
It's one of those details that could be important later (Kou and Nazuna are exchanging major lies swirling around the same topic, right now) but it's not "obviously and completely obviating foreshadowing"-tier bad.
Nah, they ain't about that anymore. They probably never were, in fact, but it became clear by chapter 87 that they don't even have it in them to kill anyone who only happens to know too much. Even now, they haven't thought of killing Kyouko-- a failed candidate and proven danger. The first thought when they figured Kyouko was hunting and killing vampires was to hunt down their weakness objects rather than "just" off her-- which would have been easier (even though it would have also robbed us of multiple character explorations). When Hatsuka separately interrogates Kou (chapter 171) and Nazuna (end of ch. 171, most of ch. 172), there's no hint that they're still holding his life with that time limit.
Maybe that's just a Hatsuka thing, but look at these women (and Hatsuka) and tell me that any of them are hard like that-- they are not. The current contender for hardest vampire on these streets got clocked so hard by Kou she's been seeing hearts since, so she's not doing a thing. The other one's much more concerned with playing cleaner for vamp society.