In immigration you are moving models to zones which have empty slots. Are u still keeping a copy of the immigrated models in their original zones as well (copy) or are U completely removing them from their original zone (cut)?

It's a copy. But it doesn't matter too much if I remove it or not from the original zone. Because that avatar (agent in a zone, I call it avatar) belons to to an old period. Even if I leave that agent there, it won't participate any other activity due to the old period is already over.