Ookay… Microsoft isn’t making it easy. They actually have different versions of d3dcompiler_47, and apparently the newest one requires some system DLLs that are not present on win7.
There is another version of DLL present in the UE distribution, :
Engine\Binaries\ThirdParty\CEF3\Win64\d3dcompiler_47.dll
Please try either a) copying it over to Engine\Binaries\ThirdParty\GameWorks\VXGI; or b) setting r.D3DCompilerPath to point to that DLL. If it works on your systems, I’ll replace the DLL in the repository.