You can manage & track your card collection and decks once you create an account and login.
As long as that character is untapped, sure. (The basic rules used with the Autobot Starter Set say that a character can’t attack twice in a row, but that rule isn’t part of the Advanced Rules.)
Correct. If you have another untapped motorcycle on your team, you can attack again. However, note that the first attacker does not have to be a motorcycle.