OK, you're excused...

[Nilpaurion Felagund]

"Does that mean Finrod was not under, or was excused from, the Doom of the Noldor?"

I asked that question on the way here, while reading the Silmarillion. I was on chapter 19 - Of Beren and Lúthien - when I came upon this line...

[Finrod: ]Your oaths of faith you make break, but I must hold my bond. Yet if there be any on whom the shadow of our curse has not yet fallen...

(The Silmarillion 19)

He was affected by the curse, but it seems from this moment, the shadow of the curse itself has been lifted from him - akin to the Christian concept of salvation from mankind's inherent iniquity. The Prophecy of the North mentions treachery, the breaking of bonds; and Finrod, despite the fact that this oath would lead to his death, refused to break his bond, perhaps lifting the curse from him. Ergo, he returned to Valinor without the long stay at Mandos the curse promised.

Am I reading too much into this?

As usual...