Is there any chance we can keep Hazard and Mata for the long haul?
No, though I do suspect it will be easier to keep Hazard than Mata. Juan just belongs in Spain.
Hazard may be easier to keep because of his age and the FFP implications that will exist in ~5 years. He will be at mega-superstar status by that time and there is a possibility nobody in the world will be able to afford him.