Upload & Sell: On
+1 on renting a duplicate body. Makes processing the pics to match a piece of cake, vs a nightmare if a different camera's rendering is off too much. Even a lens with a color cast can cause headaches (been there, done that). Not to mention, if one of your bodies acts up, having a second is a complete life saver. Also, remember to use the second card slot as a backup instead of adding to your total storage, since even cards die now and then.
I've shot a few weddings with 2x D7000 (one rented) and SB600s + my Nikon 17-55 2.8 and 80-200mm 2.8, and didn't feel the need for anything else, indoors or outdoors. Didn't even miss VR. Things tend to move so fast sometimes, you won't have time to switch around lenses on a single body. That, and a telephoto zoom will allow you to get in close without having to jump into the action yourself. Great for candid moments.
After your first wedding, you'll start to understand your own style of shooting. Review your keeper pics, and if you're in software that allows you to sort images by focal length, you'll find out what you shoot at most, and have a direction to shoot for when adding lenses to your collection (or renting for the next wedding).
In the end, weddings are a lot of work, but they can also be a lot of fun. If you don't fall into a fountain. I'm primarily a sports photographer, and at times, weddings can be just as action packed. I've had a great time at the weddings I've shot, and hope to have the chance to do a bunch more in the future with my D7100 and beyond!