ok I see what you are trying to do but I think you may be going about it wrong I am not sure.
If you have a bunch of OBJECTS in your level that have some thing in common like I saw in the video they all were square, on the floor, changed when you touched them and destroyed when you touched them again and you want to change the properties of what happens during those EVENTS you should be able to do all that with the one working blueprint.
So my guess is you tried to parent the blueprint which would work also if you have one blueprint being the BASE and then making children.
I should be able to help you with this if you can tell me what you are trying to do in the blueprints. You seem to have the right idea but you might be missing some key shortcuts or placement of nodes.