Have you tried going to the “Individual Components” tab of the VS 2017 installer and selecting the VC++ 2015.3 v140 toolset (x86,x64) and the Windows 8.1 SDK. I don’t think they are selected by any of the “Workloads” on the main screen (although they obviously should be by the “Game development with C++”) and both are required for rebuilding UE4.