Lacking essential coding utilities in the Blueprint Editor.

That sounds to me like a people problem, not a technology problem.
First, someone trying a variable without checking what it does.
Second, after trying it, not testing that it actually still works.

If you want to save someone the 20 seconds of finding the variable inside the blueprint before using it, then you can name such variables with some prefix, like “privMyVariable.”
Crude, and very effective. Assuming you don’t have problem people on the team. If you DO have problem people on the team, I’m afraid no technical solution is going to fix that for you.