Just to clarify, you aren't actually making a NEW folder, you would simply be creating a pointer under Libraries to the existing folder; it's not like your downloads data actually moves or anything. See
HERE.
Desktop is the high-level above even libraries so I don't believe it's possible to remove or move it. (Though it's probably possibly to create a redundant Library that points to it, but I wouldn't)
To remove FAVORITES from Windows Explorer:
1. Go to HKEY_CLASSES_ROOT\CLSID\{323CA680-C24D-4099-B94D-446DD2D7249E}\ShellFolder
2. Change permissions ...
- right-click on Shellfolder and pick Permissions
- hit the advanced button
- choose the owner tab
- select yourself or administrators, if you are a member of the administrators group, in the Change Owner to: box
- tick the check box for Replace Owner on Subcontainers and Objects and hit OK
-back in Permissions ALLOW access FULL CONTROL and hit OK
3. Set "Attributes"=DWORD:a9400100 (to restore it use: a0900100)