Raiden Mei does not require coordination, quite the opposite. By targeting someone to be protected and an unwitting victim, all kill abilities will affect the unwitting victim instead of the one being protected. As soon as you coordinate whom the second target is, mafia can simply target them. Raiden Mei is an ER ability, too, so can indefinitely protect someone as long as there is a scapegoat, Raiden Mei lives and binding chains does not take effect. Whether or not Fu Hua helps out and protects the scapegoat (by targeting the power role) is irrelevant in saving the power role.