MBP (late 2016) - 5.1 audio over USB-C? While I am waiting for my new MacBook Pro to arrive, I have started wondering how to connect everything together. My goal is to only have one cable to connect to the MacBook when I use it at home (which will be Thunderbolt 3 obviously). So I will probably get some sort of Tunderbolt-3 Dock with Displayport and Ethernet. 

However, I am wondering how I should handle audio: I have a 5.1 surround system which provides both digital  (optical toslink) and analog input (using three cinch cable for the different channels).

I know that I should be able to plug in a toslink cable into the 3.5 audio jack of the MBP (if Apple hasn't decided to remove that feature?). However, I would like to only have one cable as mentioned above, so I need to get the audio over USB-C / Thunderbolt 3 somehow.

Is this possible? What kinds of adapters would I need, so I can realize the following (basically I am looking for an adapter from TB3 or Displayport to Toslink (optical audio) or Digital Audio via Coax):

-------------     --------------           ------------------
-           -     -          DP==         ==TL              -
-  MacBook  -     -  Dock      -    ???    -   AV-Receiver  -
-           -     -            -    ???    -      (5.1)     -
-        TB3=======TB3      TB3==         ==DA              -
------------      --------------           ------------------

TB3 = Thunderbolt 3 / USB-C
DP = Displayport (regular size)
TL = Optical Audio (Toslink)
DA = Digital Audio (Coax)
You can also try picking up a relatively cheap FireWire soundcard. They are usually produced for con- or prosumers and are of a relatively high quality. Picking one up second-hand should not be that expensive.