Re: different clans for your OCs:
Danaë - Brujah, or even Salubri Warrior; she kind of vibes as someone who only knows how to be a warrior but wants more than the violence if that makes sense?
Emma - Nagaraja or Toreador; more leaning to Nagaraja for the magic connection but also because I can see her in a narrative of "born to be soft and kind, driven to eat flesh" kind of thing.
Elle - Malkavian or Ventrue; kind of see her embodying the idea of complete control of self, even if it means voluntarily blinding herself to things.
Eustace - Ventrue or V5 Tzimisce; all I know is August would want to eat him, but the Malkavian aspect of it would give him pause. But also, the hints of ownership over his childe and such feels very Agoge adjacent, but if they never let their childe complete it.
Do not know the others enough except maybe Irene - to which I can see as a Greek equivalent of the Lhiannon for some reason?
OOOOOOOOOOO
Very, very interesting takes! I honestly feel the same for a lot -- if not all of your points...
Danaë - Brujah, or even Salubri Warrior
She feels the closest (and has spent the most time in-game) with the one Salubri Warrior in her coterie! They commiserated with each other over their respective clan enmity and personal history with the Tremere (plenty for the Salubri on that latter point, and almost none for Danaë before she moved to Prague). They share a Road (of Chivalry, and implicitly monitor each others' progress on it). They're the heaviest hitters in the team and work well together in a fight. They have so much in common, but he's never challenged his place on the chain of command -- as a soldier just following his orders, and she's not getting any better the longer she's around him. They reaffirm each other's worst impulses and vices (the wanton killing and efficient projection of fear wherever they go); it's horrible (and I love it)!
Emma - Nagaraja or Toreador
Love the idea of a Nagraja Emma! I don't see her being as disgusted about this as I thought she'd be to be honest. Being part of Rosaleen Norton's coven in life puts her in very close proximity to the sort of magical practice that actively employs and revels in the taboo and the Abject. Rosaleen's irl Pan worship and her writings/art on it was very Verbena-adjacent. They'd be no stranger to [Marina voice] blood and guts and angel cake. There won't be any blood under Emma's nails (in public, polite company), but the smell of rot is still there under all those pressed, bleached bone-white gowns and powders and strong perfumes. Speaking of death -- she'd be a very different -- perhaps stronger and more forceful necromancer too. I can definitely see her graduating to eating the wraiths that she's currently only trying to "befriend", for example...
Elle - Malkavian or Ventrue
Really, really funny coincidence again with the former, as she'd been (negatively) compared to her Malkavian coterie-mate's very controlling sire by the man himself before, lmao. As an ex-Sabbat Malkavian Anttribu, I can see her making deals with the worst that clan has to offer, turning away from Vasantasena's movement (within a movement) and towards the likes of Eustace (who is indiscriminate about his associates) and that "odious" new Primogen in Chicago for mentorship in Talley's absence.
Eustace - Ventrue or V5 Tzimisce
My ST and I (for the fun of it) headcanoned that he's somehow unwittingly "rid himself" of Dementation in the centuries after the Great Prank (only to see it spontaneously manifest in his childe) and masqueraded as a Ventrue (with an impressively forged lineage) for a while before moving to Australia in the early 1900s. His fake feeding preference is also appropriately dated for the time: "spiritualists", and really just another cover for him to look for choice wraithly servants that occasionally attach themselves to these communities.
Dunno about Lhiannan Irene! She's a perpetual city gal who's held onto her (Orthodox) Christianity well into the Modern Nights out of spite for her sire and former adversary (Bertrada, mother of Charles the Great). It does make a *very* interesting AU, though... :)