I once needed reference to the level blue print and couldn’t figure it out. So I used an event dispatcher. I can’t tell how to do it off the top of my head, because I am not at my work station. But if you look it up I’m sure you will find tutorials on it. Hope that helps.
My best practice is to not put anything in the level blueprint if I can avoid it.
From what I can tell, you might be trying to put common methods within the level blueprint, but those would probably fit better inside of a blueprint function library.
The dispatcher suggestion above works.
One thing you should keep in mind is “coupling” with your blueprints. You want to minimize the dependence your blueprints have on other things, like a level blueprint. What happens if you make a blueprint, which depends on level specific data, and then you want to use it in another level?