Did some more testing today on my MacBook Pro, to see what works in macOS.
In Resolve I only see two inputs, while as you can see in Cubase for example, I see all the inputs.

- Screen Shot 2018-07-24 at 16.19.27.png (154.51 KiB) Viewed 2475 times
But at least on macOS there is no crackling dropping out when monitoring the two inputs. On Windows it is completely unusable.
I suggest implementing ASIO support on Windows since Windows Desktop Audio is not built for such applications. All other DAWS support ASIO and it being years around makes it a very reliable and robust system, and is specifically built for low latency audio.
Summary:
RME Babyface Pro (Multichannel IO USB Audio Interface)Windows 10: All inputs are displayed in Resolve, but only 2 inputs can be used at the same time (the ones that you choose as a recording device in the Windows 10 Sound Settings), the others are grayed out. Monitoring the input is impossible, it is full of drops (about 25 drops per second if you let me guess).
macOS: Only 2 inputs are displayed in Resolve, input monitoring is OK (a bit of lag).