Decent profit for Villarreal, assuming we’ll be paying North of about £25mill if a deal can be agreed, they paid €14 mill a year ago.
Good position to be in. If they rate him and think he'll continue to develop into a top player, they refuse to sell him for less than the release clause while offering him a new contract doubling both his salary and release clause.
If they don't see the hype and think his market value has peaked, they will go into negotiations with Everton and sell him now. To maximize profit.
That said, I am sure they back themselves to replace him. As it will be the 3rd summer in a row where they sell their number 9 for massive profit.