@Subzeroblack, the simplest way to store which pickups have been collected, and have it persist after the destruction of the unit, is to store that information in the player controller. If you make a custom event in the player controller that is called each time one of your pawns picks up an item, and that event stores a record of how many have been collected in a variable on your player controller. Then the event checks if they are all collected. If true, call an event that causes damage to your monster (the toolkit has the functionality to receive damage within each pawn, but you may have to customize it depending on your use case).
Hope that helps.
edit: i would recommend watching the unreal twitch stream on blueprint Game framework, useful primer on using game states, player states and game instances as well.
