First on your camera inputs. Inputs 1-2 are HDMI only: 3-4 are switchable HDMI or SDI: 5-6 are SDI only.
Using the USB output to a laptop running Livestream producer is easy. Since the stream comes already encoded from the TVS, there is little for the laptop to do. We have run it on MacMinis, Laptop Air, and Mac and low end PC laptops. Works with both USB2 and USB3. Works quite well and supplies quality image.