It seems the mklink calls should have the parameteres quoted, otherwise one gets this:

Make sure Fork.RI is executable in WSL...
OK.

Create 'git.exe' symlink...
The syntax of the command is incorrect.
OK.

Simply changing all mklink calls from this:

mklink %CMDDIR%\git.exe %CMDDIR%\wslgit.exe

To this:

mklink "%CMDDIR%\git.exe" "%CMDDIR%\wslgit.exe"

Seems to fix the issue.

I apologize for not being able to open a PR for this and speed up the process, sorry :(