Great work Delineator! Looks like the kind of place that is usually busy
I expect it would be exceedingly difficult to populate the render with a convincing crowd. Another approach (easier) would be to have it communicate a story as to why it is empty of people. One idea that comes to mind, based on your description of the kind of place it is, would be to turn it into a crime scene. You could draw some chalk outlines on the ground where the bodies were found and put up some police tape barriers. Furthermore the cafe tables could be dressed to look like they were quickly abandoned with glassware & dishes, and maybe table cloths with one or two pulled askew. A chair could be flipped. And perhaps the blimp could have a flood light shining down...
Regards, Ross