Rulings

Atzocan Seer's second ability doesn't include the symbol. You can activate that ability even if it's already been tapped, perhaps because you activated its first ability.
If an effect refers to a "[subtype] spell" or "[subtype] card," it refers only to a spell or card that has that subtype. For example, March of the Drowned is a card that benefits Pirates and features Pirates in its illustration, but it isn't a Pirate card.