The closest I got with adding the desktop icon to the side pane is you can add the desktop Icon by clicking the Favorites arrow.(it might be already there). If you don't have any favorites or the arrow is not there you can add the Desktop Icon to it by Clicking and holding the icon and drag it to the favorites tab..
I have not been able to figure out if you can just add an icon anywhere in the side pane my guess in no
And I have not found a way to change the icons for the libraries..(I don't think you can)
Hope this Helps..