You can insulate over the closed boxes eslewhere in the US, I don't know if Chicago has other requirements. The sharpie is a wonderful idea. I wish I had done such back when I did my own home. Just to find a luminaire device box in an attic where all looks the same and you have just a general idea of location? Sometimes the people here are beyond brilliant.
I for one welcome you here and commend your using an electrician to inspect along with your choice of careers.
