1. Can't comment on the effectiveness of CF 1-piece driveshafts other than to say they're expensive.
2. 245's will be pinched on 17x7.5. You want at least an 8, if not 8.5 or 9. They're also heavier. If you're going primarily for weight, stay with 215's. That said, there are some lightweight 17x7s out there, so you can cut weight on wheels. If you have copious amounts of money, there are brake kits with lighter calipers and rotors that will save a fair amount of unsprung weight too.
3. Flywheel, yes. Your shifting will need to be on point, because your RPM will drop faster. Pulley, no. You're not saving a ton of weight there and enough people have reported engine problems associated with lightweight pulleys that I would pass.
4. You can save pounds with a lightweight battery, but I'd want a garage or some place where I could leave it on a tender.
Look into exhaust. The OEM exhaust is freaking heavy. Aftermarket exhaust can be significantly lighter. Titanium exhaust can be tremendously lighter. Also tremendously louder.
Read
Anthony's 4 Step Diet Program for a lot more ideas on where to cut weight.
Why can't you do a tune? Premade tunes are as easy as flashing your ECU. I wouldn't get a catless header without a tune anyways; it won't run correctly.