Sorry I didn't catch this yesterday when you asked me to take a look.
On Windows, we use .rc files, not .pak files. It looks like you're
missing generation of .rc files in ash_strings.grd (they should be
<output> nodes), and you're missing inclusion of the generated .rc
files in your .gyp definitions. See e.g. how gfx_resources.rc is
included as a source file in the .gyp file in your change, and how it
is specified as an output in gfx_resources.gyp.
Hopefully with those changes the problem will be solved.