You may want to look at the functions Save and Load of BP_GameMode. This can be implemented pretty similar to how campfires are saved. For saving you use the GetAllActorsOfClass node and call the respective GetSaveVars function of your AI class. If you have created your own AI pawn class you may want to take a look at how this GetSaveVars function is handled within BP_PlayerCharacter. You add the array of structs for the AI pawns to the FSaveVars_Level struct afterwards. Loading can be done the same way like the campfire is loaded in the function Load of BP_GameMode. You will also need the LoadSaveVars function in the AI pawn class.