During the phylactery negotiations, Rifters gained the right to be a) considered people and b) convert to the Chant. Thranduil, who has been here for nearing three years, has been making polite inquiries and has found a Revered Mother who is willing to (after some minor tests) supervise his entry, as it were, and witness him not catching on fire when he speaks the Chant.

Several characters also may have noticed his relationship with Gwenaëlle Baudin, formerly Lady Vauquelin, recently revealed as the product of an affair between Comte Vauquelin and his elven maidservant. Given that there are now no reasons to keep the relationship secret for her benefit, and no legal barriers to it, the Provost of the Kirkwall Inquisition outpost will be marrying (1) Gwenaëlle Baudin in a Chantry-sanctioned ceremony come the new year.

✵ TL;DR: As part of the ongoing public relations push to improve the image of rifters outside the Inquisition, Thranduil is converting to the Chant and marrying Gwenaëlle Baudin. Per our beautiful and generous mods, only one of whom said it could only go ahead if titled as the above:
The response will be varied—some people will be scandalized, some people will think it's a bit like a circus act, others will be more open—and reactions will be further complicated by Gwenaëlle's personal situation, with a couple of people in Hightown taking this as confirmation that elf-blooded people are bad seeds who will do things like run off and marry enormous elf-shaped demons if you give them the chance. But no one will bomb the proceedings, and if everyone is well-behaved it could inch forward toward "rifters are normal people who do normal person things and don't burst into flames if they speak the Chant" progress.

THE PREPARATION STAGES

✵ Their wedding will be the last day of the year to allow Thranduil to symbolically begin First Day in 9:45 as a properly Maker-respecting, Thedosian-family-having model rifter, but most weddings take longer than three months to plan, so plotting opportunities are mostly in the semi-frantic run up, for example COMMUNITY OUTREACH (Lakshmi Bai) will be spearheading planning with regards to coordinating with Kirkwall merchants and tradesmen to give help make this political set piece an economic boost for the locals, as well as coordinating associated charitable works.
✵ Anyone in the DIPLOMACY DIVISION and/or CHANTRY RELATIONS might have a vested interest in making sure specific names (of NPCs that they have been courting diplomatically or PCs that they don't want to make a scene) are or are not on the guest list. Ambassador Amsel will have final veto power over that list, and additions she personally approves get preference.
✵ PCs are welcome to hold opinions on the fact that this is happening at all, and are invited to vent them in detail to Thranduil.
✵ Assorted wedding planning minutiae: a lot of this will be general background flavour more than anything else, but characters are welcome to get involved in it so they too can be flavourful while sewing veils and planning flower arrangements.
✵ Gwenaëlle will be involved in the actual planning of the event as little as possible.

THE ACTUAL WEDDING

✵ The reception will be held at the Hightown residence of the Duke de Coucy. The same residence where Gwenaëlle renovated the ballroom into a combat training facility, so they'll have to figure something out.
✵ There will be a log! The actual event is falling in the traditional slow period of DWRP, when we are all sleepy from Christmas and drunk from New Year, so sign-ups here don't necessarily mean you're signing a contract in blood to extensively thread anything, but please express interest if you'd like your character to be in attendance (and in what capacity) so we can figure out the best way to structure it! We will be logging the reception rather than the ceremony for presumably obvious reasons.
✵ Characters can potentially attend either as guests, members of the wedding party or on a professional basis. (Guard duty, serving staff, person-who-hands-Gwenaëlle-a-shot-every-hour as some for instances.)
✵ Characters attending as guests must be suitable or made suitable to rub elbows with Hightown elite for a few hours, can receive invites on the strength of their CR with either half of the wedding party, their personal significance (nobility, connections, rank within the Inquisition) or having petitioned Ambassador Amsel for the opportunity to contribute to the soft power diplomacy and promote their pet causes socially. (If you're going with door number three, they actually have to convince her it's a good idea.)
✵ Characters working the event must have bathed and be able to convincingly seem as if they aren't deciding who among the guests will be first against the wall when the revolution comes.

INTERESTED IN ATTENDING?
<b>CHARACTER:</b> Name McFace<br /><b>CAPACITY:</b> A guest? A guard? Something else? <br /><b>BASIS:</b> Do they sometimes call Thranduil dad by accident? Do they specialize in not looking judgmental when guarding the wealthy? Kind of want to collect blackmail material on Kirkwall's elite?