I realize that this might be a bit of an abrupt offer, but after reading Selda's personality and plots, I would like to offer Serenity as a future mate option.
While he is not a crackship, his adoptive mother and aunt certainly believe him to be a gift from the spirits. When they found his basket, it was on a moonless night, but his basket was illuminated by hundreds of fireflies dancing around his basket. Some of them followed the basket when they took it back with them and he's always had a habit of attracting the lightning bugs since popping from his basket.
Fond of glowy things, nighttime and, of course, fireflies, Serenity is turning into quite the nocturnal thing himself. He is always aglow by the fireflies that surround him and he feels naked without their presence.
I feel like Serenity would be a good fit for Selda because he could help her see that the nighttime isn't so scary after all and even with the minimal light of his lightning bug lantern (the jar he carts around with him) he could provide enough light that Selda's shadows could remain with her whenever she needed to call upon them.
(Also aesthetic reasons.)
I do realize that we already have a fling set up between Cecily and Serenity, so this offer would be valid after our first pair have their fling and Serenity learns to mature a little bit.
Okay, that was a lot of writing. Thanks for your consideration!