ranking veilguard characters by likelihood of stygia and neve having a threesome with them:
Rana - has already probably at least made out with neve before the game, after the game is detective partners with her, she almost certainly Has Thoughts on stygia, who Has Thoughts back. the threesome is almost inevitable but, if it develops into an actual polycule, so is the catastrophic divorce. even the threesome will have a layer of jealousy and competition underlying everything.
Bellara - strong relationship with both stygia and neve with enough romantic tension to make a threesome make sense. tbh if neve had not so immediately and profoundly claimed stygia's interest, bellara would have been a top contender for romancing, and we all know the potential of bellara/neve. the question is if anyone involved will take the risk to step outside their comfortable, familiar relationship as good friends and pseudo-sisters to instigate the threesome; if such a thing happens, it has a good likelihood of developing into a thriving, happy throuple.
Lace - similar to bellara, already has a strong relationship with both neve and stygia. the main obstacles are that a) lace is a bit lower on the potential romance list for stygia (nothing wrong with her, shrimply not much of stygia's type) and b) the whole "in a relationship with taash" thing. however, it still might happen. i think they would have fun but would decide to not make it a regular thing.
Maevaris - i'm confident both stygia and neve would be down, but less sure of maevaris's interest. even in the event everyone is interested, i'm not sure anyone would actually make a move. still, a solid possibility. if it happens, it might become a semi-regular "friends with benefts" thing, but only if it happens.
Evka - i think both stygia and neve are physically attracted to evka, and evka might be into them. additionally, i imagine they'll interact fairly often post-game as the wardens help with the whole blighted neve situation as well as generally restoring the peace. the main question: is evka and antoine's marriage open, and if so, on what terms? even assuming it's open, they might insist on including antoine. no disrespect to him, but that's a hard no for stygia. still, a steveka threesome is on the table, and there's even a chance (if somewhat slim) for a lasting relationship there.
Taash - main obstacles to this: a) i'm not sure if taash is really neve's type b) in terms of abstract personality and looks taash could be stygia's type but in actuality she still has some Underlying Issues from her time in the military re:qunari that she's working through but i think she wouldn't be comfortable with doing things sexually c) lace and taash are in a committed relationship. it'll take at least a decade after the game for this to be really on the table, and even then it's more likely for it to be a stygia/neve/lace/taash foursome than a stygia/neve/taash threesome, and it almost certainly never happens again.
Isabela - i think everyone here would be down for it if the idea ever came up; the main obstacle is that stygia and neve won't be getting out to rivain super often post-game, so there won't be that many opportunities for them to be propositioned. however, it still could happen fairly easily, and could even wind up a regular thing, if not an actual polycule.
Teia - physically, both stygia and neve are attracted to teia (who isn't?). neve, at least, is canonically down to date at least one crow, so probably wouldn't let teia's moral ambiguity get in the way of a good time. stygia would be more reluctant but not super reluctant; the main obstacles here are a) viago and b) i don't think stygia/neve and teia will really be interacting enough post-game for the possibility to come up in conversation. could happen, though. watch out for viago's response, though! there's a timeline where this threesome winds up causing a vicious tevinter-antivan war.
Myrna - i think both stygia and neve could be into her. the main question is if she would be into them, plus the additional obstacle of i'm not sure how often these three will all be meeting. if this threesome does get off the ground, though, they'll go down in history for producing some of the most inventive applications of magic for sex in thedas.
Morrigan - i kind of want this to happen, for Stygia's Complex Feelings on Religion reasons re:morrigan having mythal's memories, but i also think those Complex Feelings would present an obstacle. there's still the question of physical attraction, morrigan's openness to a threesome, and the logistics of the thing. not impossible though, but would almost certainly just be a one-time thing.
Irelin - in terms of "attractive to stygia and neve", irelin is basically bellara but without the deep and abiding friendship and emotional significance. sorry, irelin, but it seems unlikely that you'll get to sleep with these two. my condolences.
