I'm looking for a situation that most often occurs in shoujo, wherein a character gets close to another they are jealous of in order to basically imitate them to the degree of becoming them, replacing them altogether. That sort of horror-esque shoujo sort of thing? Usually a female character that wants the life and everything of another, generally lead character, starts by getting close to them, dressing and making themselves look like them, acting like them, and generally replacing them in every way they can? I don't particularly want a straight up horror as I generally find the art in them unappealing and am quite picky about only reading things I like the art and the story basically everything. Older art styles like older than the changes that started occurring around 2010 in most genres? Like things getting rounder, smoother, etc. I don't like hentai, ecchi, smut, overly fanservicey things, I don't have anything against yaoi yuri shoujo ai shounen ai but I don't want them for this request. I'm pretty straightforward looking for shoujo-type or shounen-type as the in large and by far ruling genre. No lolicon shotacon, any form of perversion needs to be minimal like super minimal. Minimal enough that it wouldn't bother a repulsed asexual at all. Sorry for being longwinded and I appreciate any help especially considering I haven't made any lists. Thank you for your time and help.
EDIT - HARAGURO AND IMPERSONATION type things fall well within what I'm after, if you have any to offer that aren't in those tags, I would love it.

Hmm... There's Kasane (MATSUURA Daruma) oops... You didn't want yuri/shoujo ai... There's like... Girl's kissing, but that's not what the story is about so.. Um... Still try it?

That's a good one, I know it but I like your suggestion. Thanks!