You have an excellent story here and a very interesting view as to what has happened to Maglor after those fateful words in the Silmarillion, which leave him out of the story's future, neither alive, nor dead.
I am intrigued, though, by the last parahraph. Is Maglor happy to know that he might see his kinsmen again, or does he dread the mere thought that Feanor cannot be kept in Mandos forever?
Beind a rabid Feanor fangirl, I hope they have a joyous reunion and another chance. ;)