Can't see much problems in operating one in the EU. Cygnus did it.
Many airlines are sending their fleet to all over the world for maintenance.
And at OST there are still some DC-8 experienced guys and hangar space.
Sim check could be done in the US.
DC-8-70 is cheap to get, cheap to operate, and parts should be no problem with many of them stored.
Biggest problem is getting a good flightcrew with many hours on the Eight and most of the competition is flying widebodies (A300,767 etc).
But I can't imagine this is a real request to start an airline.