Headcanon that somehow Finrod is Elrond’s most legally legitimate relative besides Galadriel, Celebrian, and his children (Aragorn excluded).
• Whenever Finrod had a Good Friendship with a Beorian they would make him a godfather of their kid(s).
• Beren is legally Finrod’s godchild (along with several other beorians).
• Then Luthien and Beren decided to honor Finrod by making him the godfather of their kid, Dior.
• By some divine humor, Dior adds Finrod to the legal family registry as his uncle or something.
• Elwing keeps the family registry as it is because if her dad claimed this “Finrod ‘Nóm’ Felagund” is family, it must be true.
• The argument can be made that Elwing left her kids, sure, but whatever anyone’s opinion about Elwing is, Finrod is still legally e&e’s grand-uncle/great-grandfather
Now for the other side!
• Finrod is Idril’s honorary uncle and legal guardian if her parents die. Because Turgon in Valinor never thought death would be a thing and he wanted to annoy his siblings.
• Idril makes Finrod Earendil’s Honorary Grand-Uncle and Legal Guardian, to keep the joke going in an increasingly stressful world.
• Eärendil doesn’t know the joke but the paperwork says Finrod Felagund is his family, and they’re both blonde so it’s probably true.
• Eärendil makes sure to put Finrod in the family registry after Gondolin has fallen and he is all grown up. Gil-Galad squints, but doesn’t question The Dreaded Finwean Family Tree™️.
• Eärendil does not think to communicate Grand-Uncle Finrod to Elwing.
• Elwing does not think to talk to Eärendil about Grand-Uncle Finrod.
And finally
• By his marriage to Celebrian, Elrond is legally Finrod’s nephew-in-law.
• By his feanorian kidnap-adoption, Elrond is Finrod’s second half-cousin.
• Once in Valinor; Elrond has to read all this paperwork and go through the slow realization of “Finrod, again.” As the sunshine elf continues to pop up Everywhere in his family tree both biological and adoptive.
Of course, there are other people that Elrond is also ridiculously related to but, the idea of Finrod “That Friendly Guy” Felagund somehow being Elrond’s most Legally-Binding relative is great.