I'm not sure I understand exactly what you're trying to say, or how it applies to the question I raised. You need what ever character/item you want to respond to scripts cross-level to be global yes. Next levels would naturally have other GUIDs as it's another level. But I'd have hoped level templates kept its content identical because added level templates should update on the fly if you edit its original source, implying they're interconnected as one constant level. Say you add Level Template A to Fort Joy. You load Level Template A and add a tree. That tree should then show in Fort Joy too. But you can't target that tree in Fort Joy unless you explode Level Template A, which is fine as that's what you do once you're done.

My issue with that is, if you want to make scripted events, such as an execution, destructible objects, secrets or what-not, that work won't be lasting if done while working on Level Template A. You'd either have to go through every item, character, etc and do a find and replace for each corresponding GUID, or do only the terraforming and decoration in Level Template A, and then make anything relying on Story Goals in the main map, which means anyone putting level templates to use, statistically are prone to have a pretty huge map eventually, and doing tons of adding new items and experimenting back and forth in a Fort Joy / Reaper's Coast sized map puts a strain even on my system.

Writing all this makes me realize, that's probably just how it is. But oh-what a missed feature and development convenience that's been overlooked.