"A-re" is a more colloquial form of "so-re," which both mean "that [object]." It is similar to "ko-re," which means "this [object]." in a more conversational sense, its Kore (this) Sore(that)...
Anata, Kimi, or Omae. The level of politeness is different but they're all "you". Although by all means if you know someone's name use that instead with "san" at the end. It is impolite to use you...
"to be blunt, it means the number two" -previous answer.This is not true. The number two in Japanese is Ni. "Do" in Japanese means "the way". For example, Karate-Do means "The way of Karate".