On the booing of Gomes: I don't like it, but I do understand. Gomes being jeered is just as much of a message to the manager as it is the player. They are saying "Why do you play this guy? He sucks," in the only way Valverde cannot ignore. The boos no doubt will cause Gomes a lot of stress and he won't be able to perform like that, but the fans already know he will be bad no matter what, so it doesn't matter.
I said this last season when Gomes got booed that I believe fans at the stadium doing it loudly enough to be noticed by everyone is a very powerful statement and can be quite influential in helping the team improve. If Valverde is too stubborn or stupid to recognize Gomes is completely out of his depth, this will likely continue, and no matter how much posters here, the players, the board members, the manager, etc try to say otherwise, the people doing the jeering are true fans, they just want the team to better, and it can't be that with Gomes playing.