This is the correct answer. After following your instruction C++ projects for UE4 4.16 loaded up perfectly and double clicking C++ classes in UE4 caused VS2017 to load the code just as it should.
However oddly enough I had previously had literally everything VS had to offer installed, for no good reasons, and did not work. I Uninstalled all that unnecessary stuff and reinstalled with only the needed stuff, and it worked.
**ok, never mind, it works one time perfectly then it comes back again. Still no solid solution for this bug. Perhaps Epic should release a hot patch for this?