The cast doesn’t make the reference, its the variable that holds the data that is the reference (or the spawned actor itself you could say), and they will reference each individual copy and not all of them. So each copy will have its own reference and be loaded separately into memory. That’s my understanding of it anyway so if another dev would like to correct me go ahead. (edit: if you are creating a reference to some other object through a cast its still the same, each on will be seperate).
If you mean multiple references from different actors to the same object then i wouldn’t be able to say anything with confidence as im not 100% sure.