This was looking to be a very hard problem to solve until I read again the first line of your message. "System is Windows 10 pro insider 15007"
The RealSense camera and the Windows Hello login system are reported to be not working in recent Windows Insider Preview builds. This includes builds 14986, 15002 and 15007. Microsoft and Intel are aware of the problem and have been working together to try to solve it. Apparently they have not been able to fix it yet though.
Edit: you may find the following discussion thread useful. It is hoped that RealSense will be fixed when the next Production release (i.e non-Insider preview) of Windows 10 comes out.