Emissary of the Sleepless’s last ability doesn’t create additional Spirit tokens if more than one creature died this turn.

Token creatures that are destroyed or put into a graveyard from the battlefield for other reasons do die—they go to their owner’s graveyard before ceasing to exist.

Emissary of the Sleepless’s last ability checks only if a creature died earlier in the turn. The creature card doesn’t need to still be in the graveyard.