Broken lcd panel ribbon Imac 27inch 2013

If that is indeed a cable and not just tape (hard to tell from the quality and angle of the photo), then it is part of the LCD Panel and not available separately. The LCD Panel is very expensive. You may as well purchase a new computer.

No idea, however if you call your local Apple Authorized Service Provider they can tell you. This is EXACTLY why you should take iMacs to your local Apple Authorized Service Provider to be professionally worked on, they are extremely easy to damage if you are not qualified to take them apart.

At this point, that is probably what I'd do rather than risk doing even more damage. However it's your computer and your choice of course.

Good luck with it and stay safe.

Please contact your local Apple Authorized Service Provider for support or use Google to see if that part is available, possibly check ebay too.