You guys should check out the Valley of the ancient, I’ve been looking for answers about making a call back when unloading and activating data layers and stumbled upon how they made the loading screen on the transitioning to the dark world.
I’m still wrapping my head around it, So I can’t say for sure this is the answer but It’s a good start.
Now that I’ve been working on data layers, I’ve also created an Actor that tracks other actors of interest within that data layer. I used that to handle every query that I needed. It’s a matter of passing and receiving data from that actor.
I’ve only started using data layers, I’m still trying to learn it. So this might not be the answer but I hope this helps.