This is set after all of Finwë's children, sans one, skipped out on Valinor, and before Finarfin decides he's had enough and comes home. I own nothing.
The coronation is a brief affair, a ceremony without pomp and with few witnesses. Darkness falls heavily over Valinor, a deep, inky blackness eased only by the lights of the lamps and pinpricks of stars in the sky. The residents of Tirion keep to their homes, never leaving unless absolutely necessary. They fear the darkness, as they must and as they ought to, and keep to their homes where they at least have some semblance of safety, however flimsy.
No one could find her father's crown, and even now no one knows what has become of it. Either Fëanáro's taken it, which Findis can believe, or it was destroyed during Finwë's duel with Moringotto, which Findis can also believe. It's probably just as well; it's highly unlikely that Finwë's crown would have fit properly on Findis's head.
Her circlet is used to crown her during the coronation, and the High Queen of the Noldor feels quite alone. Her siblings are gone. Her father is dead. Her mother has retreated to Taniquetil and none of her brothers' wives, nor would Lalwen's husband respond to her entreaties to please join her on this day. Findis is crowned High Queen, and she feels completely and utterly alone.
When Fëanáro looked among his siblings to decide who was the most likely to usurp what he considered rightfully his, his eyes and Moringotto's whispers settled on Nolofinwë. Not a thought did he ever spare in that direction for his sister Findis, his father's first child by Indis the Fair. Findis, after all, was quiet and cool-headed, and possessed nothing resembling dynastic ambitions—she took no husband, and still will not, even though now there is an even greater need for her to do so.
Findis supposes he was right not to consider her. She was never trained for Kingship (or Queenship, rather) as her brothers and their first-born sons were. Finwë never considered either of his daughters as heirs to that which was his. This never bothered Findis much. She knows a raw deal when she sees one; always has. Being the ruler of anything falls quite firmly in the category of "raw deals."
But here she is, High Queen of the Noldor.
Fëanáro never expected that it would be his quiet sister Findis, and not even bold, fiery Lalwen at that, who usurped his throne, in the end. But oh, at the circumstances…
The Valar would not accept anyone else as Finwë's successor as ruler of the remnants of the Noldor in Aman. Neither would the Teleri. Normally, the latter would not be such a concern, but to say that there are tensions between the remnant of the Noldor and the much larger surviving population of Telerin Elves in Aman would be the understatement of the Age. While the Teleri say that they would never perpetrate a Kinslaying against the Noldor as was done to them, Findis can't take that chance. It must be her.
Even if her siblings came back, even if Fëanáro himself came back, no one would accept any of them, not even Fëanáro, as the ruler of the Noldor. The only candidate acceptable is one of the first generation of Finwë's descendants, who took no part in the Revolt of the Noldor. Fëanáro led it; Nolofinwë, Lalwen, and Arafinwë followed him, even if Finwë's youngest child did not partake in the Kinslaying in Alqualondë. Findis is the only one who stayed. Findis is the only who did not rebel. She did not rebel, and she did not kill, and she does not have blood on her hands. It must be her.
Findis does not wish to be Queen. She has never wished to be Queen. She knows a raw deal when she sees one, and knows that what she is walking into right now is nothing but a raw deal. But for the good of her people, it must be her. For the good of the Noldor, what's left of them, it absolutely must be her.
The circlet is lowered onto her head. Findis draws a few deep breaths, her dark gray eyes squeezed tightly shut. She does not wish to do this, wants nothing more than to tear the circlet from her head and retreat, perhaps to Taniquetil to be with her mother, but she does not, can not. She is called upon to rise, and does so, High Queen in truth as well by right of birth.
Her circlet is light, and was crafted to be so. But to Findis, it suddenly feels unbearably heavy on her head, making her ache all over with loneliness and grief, and when she stands, she walks from the chamber High Queen of the Noldor with her shoulders sagging and her head bowed.
Fëanáro—Fëanor
Moringotto—Morgoth
Nolofinwë—Fingolfin
Arafinwë—Finarfin