2. Try clearing all caches while logged out and then restarting your browser and checking. If it’s still there, it’s possible that you actually hard-coded that into the file?
3. Yes, the demo (https://startupwp.com/demo/) has been updated, but you can only mildly see a view visual changes, you won’t be able to see the back-end changes.
What you can do, is download the latest version (from your receipt link) and then open up both your current theme’s and the new theme’s files side-by-side in your favorite text editor and you can then switch back and forth checking out the changes and probably be able to work out fairly easy how to copy customizations over from one file to the other.
Rest assured that 2.0 has been carefully and methodically improved to the point where there should never have to be such a dramatic upgrade again.