Hey Kyle,
Not sure if you were ever able to get the onboard audio working or not. I got all my parts yesterday including this board (typing from this new Hack as we speak).
In order to get the Creative audio to work, check out this link. (I hope its okay to post this link...)
http://www.insanelymac.com/forum/to...per-m3-patch-for-applehda-or-voodoohda/page-1
This worked for my board (same as yours).
From MultiBeast, in the Audio section - Install the Realtek 100 Series Audio patch.
At the bottom of the first post, there are files for 10.12. One has a working C/Sub channel, the other has the front headphone jack working. Unfortunately, we cannot have both. So pick whichever option you want. You also have to download Codec Commander. Install both of these to /S/L/E.
Finally, edit you config.plist to inject audio = 0 under Devices -> Audio, like this.
Code:
<key>Audio</key>
<dict>
<key>Inject</key>
<string>0</string>
</dict>
I will attach codec commander and the updated AppleHDA for C/Sub. C/Sub is the option I went with instead of Front Headphones.
Hope this helps.
JMac
Edit: Forgot to credit KenCar and his Z170X-Gaming 7 build on El Cap, that got me initially pointed in the direction of the El Cap fix for our board, and then followed that down the rabbit hole to find the Sierra fix ha.
https://www.tonymacx86.com/threads/success-ga-z170x-gaming-7-6700k-gtx960-with-10-11-5.192418/
Edit 2: Added 100 Series Audio Patch as requirement and removed it from being a side note that it may be required.