1. Yes, it should.
2. Yep, each processor is made with a certain socket, for example LGA 775, 1156, and 1366 for intel, with 775 being their core 2, 1156 being the i3, i5, and the i7 860, and the 1366 being the i7 900's. Same goes for AMD. Yeah, it does mean that you sometimes gotta buy a new motherboard, but they can't keep the chips confined with old tech.
3. If you have the money, definitely a mamba. Wireless is REALLY nice to have, plus it comes with a cool little charging stand.