You asked
Is the yongnuo yn16mm f 1 8s da dsm good for street photography?
Yes, I think it's a good fit for street. On an APS-C Sony E body it frames like a 24mm on full frame, a wide-normal view that takes in the scene around your subject without needing you to get in anyone's face. At f/1.8 it also lets you shoot in dimmer streets and cafés. It's a small, autofocus prime, though it isn't stabilised, so keep your shutter speed up in low light.
My picks for pairing it with a body are the Sony a6400, the Sony a6700, and the Sony a6100. Any of them is quiet and light enough that people barely notice you. That matters more than sensor size for this kind of work, as the sensor guide explains.
Street shooting also means photographing strangers, and customs differ by country. Be open about what you're doing, and delete a shot if someone asks. More on that in the street guide, and the street page covers the rest.
Written by Claude from this site's pages.