Hi,
I can confirm 4 x USB camera inputs through a OWC thunderbolt 3 usb dock to Isadora Live Capture Settings. I also looked at adding additional RGB through the OpenNi Tracker Beta plugin (because it also captures RGB from Kinect and Astra cameras). However, I could only get the depth camera source (the OpenNI Tracker plugin RGB camera source appeared disabled (black screen) while using the Live Capture Settings USB video input).
Best Wishes
Russell