Cap'NHal,
If you want to work for FedEx, then work every angle you can! I have a feeling that they would interview you because they probably feel that FedEx is a more valuable career than Sun Country. (I don't know anything about Sun Country, so I couldn't compare the two.) What they are afraid of is hiring someone that is furloughed from what they perceive as a more lucrative job and then having that pilot go back to the previous carrier.
I was just trying to let everyone know that FedEx is very cautious of hiring SOME furloughed pilots.