At least an EZ-1 has a trussed frame vs a monotube. That means you can run something through the frame and back wheel. Since you are parking in a relatively low-crime area, a 30-pound chain might be overkill. The cable/chain/U-lock issue is probably less important than making sure it's not a cheapie. I've always been partial to cables, but given a determined thief any system can be defeated.
I'm curious why you would spend that much on electrifying a bicycle, when for the same amount of money you could get a small, fuel-efficient motorcycle that would have better lighting, heavier drive train, and suspension. In short, it would be engineered for its intended use vs a bicycle with a kludged motor system bolted on.