1. Why would you buy another set of carbs when you just need a body? You can always put different jets in yours (my guess is you'll need to replace 'em anyways unless the carbs your looking at were properly rebuilt.
2. The wideband might work though bikes are tricky with multy cylinders etc. You'd be much better off to spend that $250 at a good shop which can do the tuning right. Yes I love new tools too!
3. Bikes are tuned very tightly. Removing the airbox cover will definately screw with it. Heck I had to rejet when I put in an aftermarket foam filter in my NH.