On the wizard side we have a clue to the identity of one of the wizards in the grey council. During the battle in changes, Harry hear someone yell "Fuego". Most of the older wizards don't verbal out their spells. We can then assume that this is one of the less experienced of the members of the grey council. Have we seen anyone that fits so far?
Or it's one of the many Spanish speakers in Mexico telling other Spanish speakers to fire their guns.