Don't know if this helps, but EF does show 2 Saga seats available (on both FI680 and FI 682) for award redemption on that date:




Departing Flights
Search Departing SEA on 02/18/17 12:00 AM for KEF
Flying FI on booking class Z
Direct/Non-Stop Only

Departing 02/18/17 - Saturday
Flight Stops Depart Arrive Aircraft Frequency
Reliability
Available Classes
Description Code Seats

0 Connections


FI 680 0 SEA
02/18/17
3:30 PM KEF
02/19/17
6:45 AM 75W
Unavailable
79% / 27m
Business - Award & Upgrade Z 2



0 Connections


FI 682 0 SEA
02/18/17
3:30 PM KEF
02/19/17
6:45 AM 75W
Unavailable
88% / 10m
Business - Award & Upgrade Z 2