icons to .desktop files

I have added icons to those with nodisplay set to true as well. In some future there will come an icon manager that allows dragging these files to desktop, and then we need icons for all apps.

Is it possible to simplify the names in /usr/share/applications/, or will that give any conflict? - I can't see the problem, but this is sure not my department. And is it possible to use spaces in the filenames. I think of something like
Pmount-mount-unmount-drives.desktop = (Un)mount drives.desktop