Using 'alternatives' for player loot table player head drops

Hi! I''m having a bit of a hard time using the alternatives entry type for a datapack I am creating. Here is what the datapack is supposed to do: - Players will drop their heads on death - If the player has a UUID that is listed in one of the conditions then the player's head will have its NBT modified to associate the player head with a particular sound (using a resource pack) - The player head is supposed to have its lore modified to say who killed that player - If the player's UUID is not listed in the list of conditions then a default sound is associated with that head Only thing is: I cannot get that last bit to work. If I try associating a default sound with a player who's UUID is not listed then I get no head drops. Removing that bit from the json allows heads to drop like normally if the player's UUID is listed. How can I add an entry to allow a default sound to be associated with a player head?