1. To disable the Ribbon, use Winaero's Ribbon Disabler:
http://winaero.com/comment.php?comment.news.20 (note: it's only a recommendation for your convenience, we bear no responsibility for third party tools).
2. Disabling the Ribbon will return the icon slider.
3. You can do this already. Go to Customize Start Menu tab. Double click "SearchMenu" and check the target from "search" to "search_files". Also, check the box for "Split button item" so you can click on it to open it. Alternatively, if you don't want it to be a split button item, double click on it to open search directly.
You can do the same for Settings. Double click "SettingsMenu" on Customize Start Menu tab. Change the Command to "control_panel".
4. On Windows 8, there is a bug that causes any dialogs opened while the menu is open to go to behind the menu. That is why the menu closes. On Windows 7, it doesn't.
5. Not sure what you mean. You can show or hide desktop icons by typing: desktop icons into the Start Menu's search box and choosing "Show or hide common icons on the desktop". You can change their size by right clicking in an empty area of the desktop, and choosing View -> Small/Medium/Large icons. Once the slider returns by disabling the Ribbon, you can browse the Desktop folder and change their size from Explorer too.