Welcome to the forum, Brad!! I wish I could answer most of your questions, but I am a 10 year owner of a gas smart. There are many ED owners on the forum that should be able to offer all the help you need.
1. Basically, yes. The BMS will absolutely prevent overcharging, but if you run the battery down to zero so that the car stops moving, but then let it sit for a bit before trying to drive again, it will go some small additional distance. If you do this several times and then let it sit at that very depleted state for a long time, like a week or more, you could brick your main battery.
2. Maximum charging speed is around 3.5 kW for a US car. European smarts had a 22 kW chargingn option that was never available in the US.