You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
You didn't mention the key factor of whether you mean the car is inside our outside. If it's outside and really in those 0 degree temperatures, no, definitely not. If it's inside a garage, where it gets to stay above 30-ish degrees? Then...maybe...barely, but I wouldn't count on it.
NEMA 5-15(12A/120V continuous) or NEMA 5-20 (16A/120V continuous) outlet?
That depends. If the car is protected from wind it should charge on a NEMA 5-15, but will lose a few percent SOC during preconditioning. A NEMA 5-20 outlet can cope somewhat better and might still charge if the car is exposed to wind, but again will lose some SOC when preconditioning.