The WDF (both UMDF and KMDF) files in the WDK are not found in a single directory, rather they are spread out across the entire WDK directory tree. Why? Because the WDK is not just WDF J and the WDK has directories for different purposes, so replicating a specifically purposed directory (like redistributables) under a WDF tree doesn’t make much sense. Here is a table of the components and where you can find them (assuming your current directory is WinDDK\6000)
Header files required to build KMDF and UMDF drivers.
Static libraries that are required to build KMDF drivers (UMDF does not require a lib)
Redistributable UMDF and KMDF co-installers, that ensure that the latest version of the framework is installed on a user’s system.
Debugger extensions for use with UMDF (wudfext.dll) and KMDF (wdfkd.dll) drivers on supported architectures
Tracing format files
Trace format files for the trace messages generated by KMDF libraries and co-installer.