This is the only part where we disagree. The Bolt EV's regeneration is severely limited when the battery is >85-90% SOC to that point that, in my opinion, it could get dangerous if you are accustomed to L/regenerative braking at lower SOC. The Volt's regenerative braking was inferior overall, but it was more consistent.
Others have answered your other questions, but I can speak to #5 and #6.
#5: I don't know what you mean about "cuts out," but the point at which energy required to overcome aerodynamic drag exceeds the sum of all other energy occurs in both the Bolt EV and the Volt way before 58 mph (it's probably closer to 40 mph). However, if you are referring to how much "faster" the Volt's battery depletes at higher speeds, they are not comparable. My recent trip, for about 160 miles, my average speed was 70 mph and the average outside temperature was 40 F. Using climate control sparingly, I ended up getting about 3.1 miles/kWh, which is about 23% worse than EPA estimates.
#6: The defogger on the Bolt EV is amazing. It is as good as the defogger on any ICE vehicle I've owned. You pay the price with about 6 kW of draw from the battery, but it will defog a completely fogged up windshield in less than 30 seconds.
