And the tears come!

I love it! Though I think you forgot to add the part where Fingon actually flees upon seeing his orc band get totally owned, and there was no bridge, so taking Bucky's line and sticking it directly in here didn't make sense.
But, overall, I liked it! Maedhros is going to be in trouble mentally for a bit. Until he figures out Fingon was made a thrall and determines to finally return the favor and save him this time.

I was hoping for a happy ending, but this is the Silmarillion. What was I thinking?

Ouch. How could youuuu? This hurts to read ;)
*goes into a corner and weeps*

First of all, excellent idea! Though I was expecting Nelyo to be Bucky's counterpart, due to Thangorodrim, this is perfectly fine. This is going to be interesting!

AAAAAAAAAAIIIIIIIIIGHHHHH FEEEEEEEEEELSSSS THIS HURTS SO MUCH!