1. The official name is: window list
2. In Kubuntu, pressing Alt+F5 will show the window list, where you can use the cursor keys to cycle through the windows. The down side to this is that it will list all windows on all desktops grouped together. While it may not mean much if you only have 2-4 virtual desktops, having 6 or more will be confusing. Also, you can change the default keyboard shortcut for showing the window list in System Settings > Regional and Accesibility > Keyboard Shortcuts > Global Shortcuts tab > Desktop group (or type in show window list in the search bar on top).
3. It's a possible addition. I know of know key event complexities involved. No need to change any code.
Hope that's what you are looking for.