File path conversions - Windows to Linux +GRAMPS

[NoOp]

While I'm in the process of upgrading my brother's WinXP computer, I've
installed Gramps 3.2.3-1 so that he can compare/use. He currently uses
Rootsmagic, so I exported as a GED and imported into Gramps. All is well
on the Windows machine; all records came across (8758 people, 2145
unique surnames) and the graphics (many) are appearing fine.

I've exported the whole thing (including media) to a .gpkg (654.3MB) so
that I can use on my linux systems. All of the entries came across w/o
issues, but the problem is the media path/graphic naming conventions
that he used. An example:

C:\My Documents\My Pictures\<surname> Geneology\<surname>, <firstname>
<middlename_or_initial> Certificate of Birth.jpg

Some are even worse, and longer with added subfolders for individuals,
pound (#) signs, etc., but that's pretty much convention he's used. Made
sense to him so that he could easily look at the files in WinExplorer &
see exactly what the files pertain to. Unfortunately the spaces, commas,
periods, # signs et all are creating issues. My system reads them
properly, i.e.:

/home/<username>/<somename>_xml.gpkg.media/My Documents/My
Pictures/<surname> Geneology/<surname>, <firstname>
<middleinitial>/<sirname>, <firstname> <middleinitial>. Certificate of
Birth.jpg

But I'd like to figure out a way to clean all those up to no spaces,
periods, commas, etc.

Any suggestions on how I can batch convert all of those to
path/filenames? Or am I doomed to having to go through each one
individually?