The level blueprint is actually a really bad idea especially if you’re spawning stuff in later on.
Handling new spawned things in the LBP is pretty clunky and hardly works at all (you have to get all objects of that type and then filter).
Especially object specific stuff (like the collision and explosion) should be done inside of your actor BP itself. Just take “on hit” again. Spawn the explosion, trigger an event which will soonish spawn a new instance of that object and destroy it.
Pretty straight forward. Tell me if you need it a little more in detail. I can set some pictures up real quick if you need them 
EDIT: Just as guideline. Everything which is not a one or two time event or relies heavily on which other objects are spawned in the level and especially interactions between two objects via “overlap” or “hit” should always be in their own blueprint.
Keep in mind that you just crowd your level BP and that this one will only work for this one level. If you want a second one you would have to copy everything (you can copy the level as well but I think you get the point). It’s just cleaner and better organized if you use the graph of each object.
EDIT 2: If you already have a question about exactly this you might wanna simply update that one rather than posting it a second time.