What about Sarah? Is she just high 24/7?
I don't know much about Sarah. TBH she didn't really interest me, and on a lot of the character walkthroughs her path was "non-viable", so I never even got drawn into it as a side story like I was with Jules, Trish, or Ash. It doesn't seem like she's very popular in general with the fanbase either, so I think the dev hasn't put as much time into fleshing out her backstory as with other characters.
And Emma, I'd say she's my favorite so far
Emma's curiousity and openness are indeed great; she seems a bit more normal and down-to-earth in her motivations to uncover "secrets" in town, so I didn't mention her in the list because of that. I really do want to see her reaction to finding out about some or all of the wild and strange happenings in Branchfield. She should be very excited at the information...and "appreciative" towards the MC for sharing those tidbits too I would think.
Like I said, even the ones I didn't include are characters whose stories interest me. Katy and Rachel are two that I really like and find attractive, but I didn't mention them because they don't have as distinct of backstories as the others (at least not yet...considering they're both friends of Zoey I wouldn't be surprised if they have one or two secrets of their own). Still, even if they remain their everyday selves and don't turn out to be secret agents sent from an alternate reality or something like that, they're still both really hot and sexy, and that's definitely not a bad thing to be in an adult VN.
Honestly, there are at least a couple other stories I could name on this site that I can respect because they're decently well-written, popular, and well-crafted VNs, but the more those stories seem to try everything to elevate themselves above being "just fap material", the more they just turn their "love interests" into something bland and unattractive to a general reader I find. Being ambitious like that is okay, but you can't do so in neglect of – or in opposition to – the ultimate foundation of a good adult VN: having attractive and compelling love interests. In that respect, I'm very glad that Element 174 has an embarrassment of riches when it comes to hot and sexy women to meet and interact with. There are too many other games out there that drop the ball on this simplest of concepts.