Sorry for the late reply.
> I recently took over maintenance of the LaTeX package lyluatex and
> noticed that several users have reported issues on Windows with
> MiKTeX. [...]
>
> In short: I am seeing Ghostscript `/rangecheck` errors in
> `--.parsecff--` when converting LilyPond-generated EPS files to PDF
> on Windows.
Please provide such an EPS file (created by LilyPond while running on
Windows) for further inspection.
> 1. Is this a known version compatibility issue between LilyPond
> 2.26.0 and Ghostscript 10.07.1 on Windows?
I'm not aware of any special gs behaviour on Windows.
> 2. Which Ghostscript versions are expected/supported for LilyPond
> EPS/PDF generation on Windows?
You are the first who reports this particular problem, AFAIK.
> 3. Should MiKTeX users pin LilyPond/Ghostscript versions, or configure
> LilyPond font/resource paths explicitly?
They shouldn't.
Werner