@Everynone Okay, there’s actually one thing left to sort out. I forgot that the nodes on the right here…
…are needed in order for the keys to toggle on and appear in the player HUD. 
I tried adding them here, but it looks like the Add to Map only allows one thing to hook up to.
EDIT: Okay, after a bit of experimenting, those nodes in the original Keycard_BP can stay where they are. I’ve also put the Destroy Actor back in there rather than after Add Map in the FirstPersonPlayer_BP. Things are looking to be working correctly and they appear in the HUD again. 