Hi Chiddo,

"Failed to unload offline registry: {bf1a281b-ad7b-4476-ac95-f47682990ce7}D:/Temp/MDTUpdate.7768/Mount/Windows/System32/config/SYSTEM, the client may still need it open."

The issue may be caused that the registry "{bf1a281b-ad7b-4476-ac95-f47682990ce7}" is been used and  it cannot be unloaded .We can use the process monitor to check which process is using the registry.
Process Monitor v3.1
https://technet.microsoft.com/en-us/sysinternals/bb896645.aspx

"2015-02-02 16:52:34, Error                 DISM   DISM Package Manager: PID=7876 TID=6008 The package Package_for_KB975496 is not applicable to the image. - CPackageManagerCLIHandler::Private_ProcessPackageChange"

The KB 975496 is not applicable to the image .This KB is applied to Windows 7 Ultimate and Enterprise and server 2008 R2 Datacenter ,Enterprise and Standard  .Please check the system version of the image .It is recommended to uncheck this update to have a try .
Here is a link for reference :
A computer stops responding during shutdown if BitLocker is enabled on the system drive on a computer that is running Windows 7 or Windows Server 2008 R2
http://support.microsoft.com/kb/975496

Best regards