On the basis that EK did indeed apply for slots at NCL for a second daily service, there must be some work ongoing to look at it. I can’t think of any airlines, let alone those of EK standing, who apply for slots to cover things they have no intention of doing !
If NCL get this, regardless of whether or not EK return to EDI, then good luck to them. I can’t see NCL being a substitute for EDI. Probably more like with no TK, QR at NCL, they have a captive share of a smaller market rather than a small share of a bigger one.