So for this reaction, is this correct:
No.
First of all, there is no such reaction.
K(NO3)2
No such compound I am afraid.
Na(NO3)2
No such compound I am afraid.
FK
Correct formula is KF.
And spectator ions are K+, NO3-, F-?
Close, but even that is not correct. There is no reaction, so technically all ions present can be considered spectators.