There is only one scene bugs me which is after first fight of MC, there was a brief scene that shows Elspeth watched the fight and she looked genuinely disturbed. If what I see in Elspeth accurate, she should have been excited, pleased and even relieved not disturbed.
It can be both of these things: Els is fascinated and excited by violence, but after her experiences in the military those strong emotions have now become associated with equally intense feelings of regret and shame. So she no longer has a safe way of expressing them, and they greatly disturb her. Thus she has created this façade of "pacifism" to help her avoid any situation where those baser instincts arise. Except with the MC it seems, who may allow her to understand those violent tendencies in a controlled environment, or whom she has made into a kind of "redemptive avatar" to be saved (and thereby atone for her own sins), or something else entirely.
I admit these are just my own speculations about Els's motivations, and there's a lot we don't know about her at this point in the story. I mean, if
only we had a scene of a genuinely conflicted Els admitting that she both loves and hates her brother (as she seems to both love and hate violence), and recognizing this same issue in a suffering Vi to help her, thereby allowing Vi and the MC to talk about this kind of dark emotional complexity. If only we could point to some reasonable establishment of this overarching theme that "love and hate are often two sides of the same coin" previously in the story.
I see Elspeth snaky, up to no good person with shady background. So I see every action of her in that sense and I can find hints about that almost every scene of her.
As I said before, if there is nothing a person can theoretically do that isn't interpreted negatively, then the actual problem lies elsewhere.
Vi was heading there steadily, she came onto MC by herself on Christmas, also at the lake too.
Yes, there are a lot of indicators that Vi would have gotten there without Els's help. So my suggestion that Els was the main reason Vi confessed is one I have definitely softened on as I consider it further. But that doesn't take away from the fact that Els did challenge Vi to be more confident, and complimented her when she demonstrated that courage ("Much better."). Even if that didn't do much for Vi's belief in herself, it also didn't completely
destroy her self-confidence in a "My, what beautiful scars you have" kind of way, which Els could have just as easily done, and is what a "snaky, up to no good person with shady background" character would have done to Vi when getting her alone.
I interpret this whole scene as a declaration of war to the most likely candidate that MC can feel things. Iirc, kitchen kiss scene was after this scene so I saw that as first blood draw from Elspeth.
The kitchen kiss only happens if the MC sleeps with Els, so it makes sense they would be affectionate with each other the next morning. If they aren't together, Els doesn't declare war in this or any other way. And that is significant, because even just being "friendly" with him by patting him on the back in front of the group would have social repercussions. Indeed, Vi saying that she and the MC were going on a "picnic" to bond that morning was her own similar declaration to all the other women. My point is that these things are not overly remarkable. In fact, here's a strange recollection: I once had a co-worker who got into a fun conversation at a social gathering with an old female friend he hadn't seen in a while, where the two of them talked passionately at length about their shared musical interests, and he told us that his fiancé – who had been there listening – later that night threw her engagement ring at him when they were back home because this devastated her (now this is a bit extreme, and his now ex-fiancé obviously had other mental issues and perhaps previous relationship concerns, but I'm relaying this unfortunate example to make a point about how even seemingly unremarkable interactions between people can be perceived when it comes to the cutthroat world of human dating).
I admit that Els did lay it on quite thick in the "kitchen kiss" scene (complimenting the MC's performance in bed, serving him coffee before partaking herself), but it was interesting to me how she chose to make these "social statements" in a very direct way, without any hidden agenda. And she didn't bat an eye at Vi's desire to "bond" with the MC on their picnic trip, nor do I expect her to raise it as a concern in the future or forbid the MC from seeing Vi in any way. IMO Els is fighting fairly for the MC's love and affection, as is her right, and not acting in an immoral manner (of course her motives behind the "information gathering" are the big question here, but those are not certain, so that reveal will be an important deciding factor in how she is judged).
At this point, Vi knows that her brother has done something that hurt Valentine, and that Valentine is capable of extreme acts of violence (when it's warranted). If you promised to tell her about it, she'll ask about what happened later. For me, her concern comes from a place of love and care. I also love this reversal of the roles, where Vi is taking initiative to be there for Valentine, while she's always been the one in need.
There are indeed a lot of positives that happen in that picnic discussion. Vi knows that the MC trusts her with this big secret he has been keeping. And the MC is relieved that he is not hiding important things from Vi, and that he can rely on her in some ways (though there's an important caveat here, which I will explain later). So the two really do grow closer in a real sense after this heart-to-heart, and there is now a strength in their relationship that goes both ways, instead of the MC just being Vi's "knight in shining armour".
My concern is that role-playing as the MC in that scene left me feeling a bit worse off than when I entered it. I became worried about Vi, because I didn't want to make her hate her brother more. But most importantly, I didn't want her to feel responsible for his actions, since he's her close family member (indeed, the MC even responds with "You didn't do it" after Vi's first words after hearing the story are "I'm sorry", which honestly broke my heart to hear from her...this is why I have a caveat about her taking on a reliable and supportive role towards the MC, since she reacted in the exact distraught and conflicted way I was worried she would). I kind of imagine the MC is feeling a bit more stressed after sharing this information with Vi, and this discussion might not be quite as therapeutic as you suggest. I do hope she is mature enough to deal with the likely feelings of guilt for the extreme harm her brother caused, but it's got to be a bitter reality for anyone to have to deal with when someone they are close to acts in such a horrible way. Especially when they hurt another person that you care about. In that sense, I really do understand why it took so long for the MC to talk about it with her.