Wizz Air coming here may depend on the kind of deal that they brokered with LPL. If it's "exclusive northwest England", then I guess we can forget about it as they would have to negotiate with LPL to allow them to break the deal, and with easyJet having already done that, I expect LPL to deny them.
As for Fedex, who knows. The only two reasons could be that as they've operated here for a year, the discount scheme has come to an end and the higher charges are now making the route uneconomic or a combination of the new tax that's due to come into force where it's based on aircraft and not passenger, and high fuel charges (the latter having temporarily seen of some of our Chinese routes).