1) Yes. Borrow one from GT. There's a thread for it, IIRC.
2) Use the component cable from your old console. It still has the same connection.
3) See 2.
4) No. The old ones are horrid angry little pieces of technology designed to kill your happiness and your libido. It puts little pieces of glass in your sandwich when you're not looking. Also, I think the drives may violate some sound laws.
I *would* call and see if they'll include you in the warranty anyways, though.
5)I'd pay the 50bux for the new one. Look for the holiday bundles out there. I understand you don't want Kinect - makes sense. But you might enjoy it with the dash update.
Either way, I'd call first and see what they say. If you've never used the warranty, they may still take it in for you. You win bees with honey, not vinegar.
Also, look at getting the basic 4GB model and add the hard drive. Also remember you're getting a new controller too, so factor that into your cost analysis.
Lastly, they have this: http://www.amazon.com/exec/obidos/ASIN/B005VBVQBU/37298120-20/
Two decent games, extra controller, and the 250GB unit (which I believe is just a 4GB with the harddrive preinstalled).