Grind the peas in a food processor or crush them in a resealable plastic bag. Spread the crumbs on a plate. Repeat these steps for the granola, then the gingersnaps. Combine the Parmesan and fennel on another plate.
Shape the cheese into balls, working with about 1 rounded tablespoon at a time. Roll the balls in the coatings.
In Advance: Roll the cheese into balls and refrigerate them, uncoated, for up to 24 hours. Roll the balls in the coatings no more than 1 hour before the party.