So Watford are demanding compensation for Silva. We want their best player, so agree to overpay a little to secure him. Suits everybody really. Player gets a move to a bigger club and probably a very healthy payrise, Everton get the player that they want and Watford can pacify the fans with the old "it was too good an offer to refuse and the player's head was already turned". Everybody walks away happy and there's no longer any need for the shenanigans around Everton tapping up their manager, so everybody saves face.
I have liked the look of Richarlison, although I have not seen a £50m player there. Hopefully, the add-ons are for shit like him scoring the winner in the next World Cup finals in Quatar and winning the Champions League with Everton. That way, if we have to pay the add-ons, he will have been well worth every penny.