It is really strange that deleting the main drive (Appl_SSD etc. ) didn't fix the problem. If I had to guess, I would say your firmware may be out of whack (from what the previous owner did) and that is what is causing your system to get stuck. Unfortunately, that is where the Configurator app would come in handy.
If you call Apple, they will want to charge you for the phone support and I don't think they would be able to get this going without hands on. Is there a local Mac shop in your area?