I experimented with how the icon looks with different backgrounds, for point 4.  Because the paper holes are transparent, white is bad, proposed light gray okay, black is good.  Overall white on black is better than white on current dingy gray, so I consider making the background darker rather than flipping colors a possibility.  I would suggest using user's color scheme (which has be requested for dialog in general) except that icon on white looks so poor.  The htest makes experimenting easy.  If you get to 4, give your opinion.

Another option would be to redo the two files.  They are private copies and I believe not used otherwise.