Thanks for the reply!
I *believe* I'm failing at step 3. However, the dd command I'm running definitely works - I've confirmed as much by running it manually while live-booted into WinPE and the installation works.
Based on the logs near the end, it would appear that there is something else causing step 3 to fail - I think it is that none of my files are present somehow. If you look at the log-section below, you can see that after disk cleanup finished successfully there is another error (perhaps more telling) : "nPos != String::npos, HRESULT=800700a1"
The process around "User did not specify a local data drive" also diverges from the logs in the beginning. It first checks is drive X:\ is right, passes over it, and then fails (early in the logs it does this process, but proceeds to locate drive D:\ and use that.
SO I am suspicious that perhaps my disk-clean operation is destroying the dd.exe file and image that I downloaded to use in this imaging process?
I'm pretty new at using this tool, so any insight at all is helpful!