Depending on the tasks that I have my slaves doing I like to alter their outfits to reflect for organization. Example would be farmhand attire for those working in the field, hard hat etc for those working as scavengers, etc. etc. I noticed that the only enslaved who tend to be have the ability to trade items are the ones you enslave in a city like Goodneighbor or out one on one in specific settings. I wish there was a way to do that to all the enslaved including the ones you enslave when you conquer a settlement to make it a slave outpost.