When he turns a few seconds later, the guy on the left side of the screen in the background (black/dark grey shirt) looks like the person who is posing for the caricature, while you can also kind of see the top of the head of the person drawing the caricature off and on after that, with no one else visibly standing or interacting with guests. That said, at the spot you marked, I definitely hear, "Come get a drawing, y'all," and at the 5:58 mark, "It only takes five minutes," which lines up with what your friend said.
But whoever is yelling seems to be coming from off to the right/somewhere in front of the person filming. (Maybe why he turned the camera?) So the barker is either in the walkway out of frame or somewhere at a distance from the actual caricature spot and not actually on camera at any point, IMO, but I'd agree... I don't think I've ever heard someone calling out at people to do the caricature, so this is weird. It's like shopping mall kiosk behavior, hah.