Hmmm.
Just summing up my thoughts, for I am of 2 minds.
It was clear from the start that it was either Curufin, or his father Curufinwe, also known as Feanor.
But then the clues.
The Saraman reference is to Curunir which works for both of them; Curu being skill or cunning, as in Skill of Finwe or the cunning mind(Curunir).
The dogged by one of his brother's lost possessions doesn't work for Feanor, presumably refering to the Silmarils. But it would work for either of his brothers Fingolfin or Finarfin. I suppose both of them start with Fin which could be the "Named with the family name" just as much as Curufin but then doesn't fit the Saruman bit.
His rival's great grandson in presumably Earendil, which points to great granddaddy Fingolfin. Which then points back to Feanor. Aaaarrggh.
On the other hand Earendil's other great granddaddy was Thingol, who doesn't really fit the rivalry bit.
Or we move to Curufin whose son was Celebrimbor, creator of the rings and maybe then the great grandson is Elrond (who had one of the rings),or Elros.
Curufin had a bunch of brothers but I'm a bit lost with the lost possession bit, here. But I'm definitely tending towards this answer.
Main character Curufin
Brother probably Maedros, but I'm not at all certain what the lost possession is
His son Celebrimbor and his possessions the rings
Giving an air to Elrond, Great grandson of Turgon?
I'm not at all happy.
So! More research required.