The total Jewish population in the North East of England is around 3,500. London, Manchester and Leeds all have much larger Jewish populations (some 40,000 in Greater Manchester alone). I cannot see how this amount would enable NCL to sustain a TLV flight.
As for Wizz Air, a possibility I suppose but I believe the Polish population is declining.
Vueling, NCL already has EZY (BCN) and Ryanair (Girona) who serve the Barcelona market, I don't believe there would be enough room for a 3rd carrier. Palma, Alicante and Malaga could be possibilities as we know the Geordies love the sun.
Oslo, I don't think we'll see again. If anyone was to operate it, then possibly bmi in between the BRU flights.
I'd still like to see Santorini return, it's a nice holiday destination,