Can I {Syncopate} for 0, and have it target its self, and then exile it with {Nivmagus Elemental} to basically put two +1/+1 counters on it for {U}?
Yep. {Syncopate} doesn't say "{X} can't be 0."
You can't make it target itself. And here's the Comprehensive Rules, to tell us why:
114.4. A spell or ability on the stack is an illegal target for itself.
I didn't see the target itself line. :P
Sleeping at the wheel here.
Tyvm