Superficially… Im unable to see why it fails to create its device. I don’t see where the integration could got wrong. I changed one WaveWorks related source file to get the UE4Game targets to build (it was using the stats interface, which need to be guarded by #if STATS, and wasn’t).
It might be that the nvidia libraries don’t match up from the different branches, I think the VXGI branch changed one dependent libraries, nvapi I think. Or Im just dumb 
Probably that one. lol
Ill continue looking at it, if it was me Ill post it , else I gonna open up an for it on GitHub.