Mar 13 2013, 2:06am
Tolkien does mention how Feanor felt about them in the long version. It's funny that your rhetorical question is actually answered by the author himself!
he had little love for Indis or her children, least of all for his half-brethren.
Ok, so I was mistaken and that actually comes from "Laws and Customs", not the final version of the story. But it still does clearly show that Feanor did not like his half-sisters. Obviously, his dislike for them couldn't be referenced if they weren't, though.
You said it was fine that they weren't mentioned because they were never spoken of again. In the late text I referenced yesterday, the daughters of Finwe are mentioned again, though there are only two there. One, the eldest of Indis's children, stayed with her in Valinor, but the younger went into exile with Fingolfin who was said to have been "most dear to her of all her kin".
"Now this babe was of greatest beauty; his skin of a shining white and his eyes of a blue surpassing that of the sky in southern lands - bluer than the sapphires of the raiment of Manwë; and the envy of Meglin was deep at his birth, but the joy of Turgon and all the people very great indeed." -The Fall of Gondolin
(This post was edited by Ardamírë on Mar 13 2013, 2:10am)