Hi hehe,
I was not at home last week.
It seems that the Realtek Audio driver needs wdmaudio installed before.
The installation with the previous version was hiding something else, probably.
I do not really have time to look at the Audio script before Thursday.
You can try to copy manually :
[Win8.1Source] DriverStore\FileRepository\wdmaudio.inf_x86_e7ccd91d9274a785 or wdmaudio.inf_amd64_fbf94909f1ca7601
with MsApoFxProxy.dll, SysFxUI.dll, WMALFXGFXDSP.dll in Target\Win8.1SE\Windows\System32
and drmk.sys, drmkaud.sys, portcls.sys in Target\Win8.1SE\Windows\System32\drivers
It should work better

About latest version, it seems better to use boot.wim drivers hive, It match the Driver Store also coming from boot.wim and it seems to solve some USB3 issues
