If you actually want these "30+ icons" in the theme, you need to fix it.

Do a windows search in the Ghost theme folder.
Search for the text "IconsDir" in any file.

Then take a look into the files that come up, and run a search in the texteditor for "IconsDir"

Look at the icon file (.ico) that line points to,
then do another Ghost folder search for the name of that icon.

If its in a folder like Ghost\Misc\Icons (or something), set the IconsDir as that path,

then hopefully all the icons will show up where they are meant to.