2. Yes I wouldn't have tested it if there weren't any there. The Downloads folder is in List format, only my image folders do I have set to display Thumbnails.
Telling if things are being scanned is now a little more difficult as the option to animate the tray icon, although enabled it only works for the web shield scanning (a bug that has been acknowledged, awaiting a fix). I monitored the Task Manager for activity on avastSvc.exe, CPU remained on 00 and no increase in RAM used when the downloads folder was opened.
3. That is your choice, but this will still be scanned.