My reason for not wanting Celebrimbor’s mother to be a Teler, which might not actually be super reasonable, is that it feels like Tolkien has this model of moral goodness where if your mother is stubborn or proud or independent, then you’re guaranteed to turn out troubled anti-hero at best, villain at worst
(I’m thinking of Míriel, Aredhel, Morwen, arguably Erendis)
and if your father is stubborn and proud but your mother is sweet and virtuous (or a literary non-entity), then your mother will be a tempering influence on your personality and you’ll turn out all right
(this is explicitly said to be Nerdanel’s role, but Melian might actually be a stronger example).
And also there’s this thing where the Noldor are the troublemaker Elves, and as Jess has observed, a Silmarillion character is less of a troublemaker to precisely the degree they’re less of a Noldo.
And so maybe this is totally irrational, but making Celebrimbor’s mother Teleri feels like ‘explaining’ how unhesitatingly good Celebrimbor is. Building friendships and alliances, repeatedly making hard moral choices under pressure and getting them right, concealing crucial information from Sauron under torture as he dies… He makes a lot of mistakes but he never abuses power, he’s never condescending, he’s pretty much universally motivated by compassion and a desire to help the world, and he owns up to his mistakes and acts to mitigate their effects as quickly as possible.
And none of that needs explaining in hereditary terms. Celebrimbor doesn’t have to be like that because he got Fëanor’s talent from his dad but Niceness and Wisdom from his mom. I actually imagine him as being very similar to Fëanor in terms of temperament as well as talents, and the reason he’s so different in his choices is because he’s utterly determined to avoid Fëanor’s mistakes. Whatever he is, whatever choices he makes, they aren’t explained in any sense by the virtuousness of a mother he hasn’t met in two thousand years. They’re consequences of the identity he spent several thousand years carving out for himself in the absence (or maybe we should say, the vacuum) that both parents left.
And he goes ahead and makes the exact opposite mistakes from Fëanor, trusting and collaborating too readily, extending the benefit of the doubt to Annatar when Fëanor would have slammed the door in his face. It’s brilliant and it’s devastating and it’s really important to me that Celebrimbor doesn’t need any justification except on his own terms.