JRail Pass right for me?

My family is going to be visiting Japan next week, but we have some questions before purchasing these passes

1. We will be arriving in Japan at the Kansai International Airport. Will it be possible to pick up the passes there?
2. Do we need to make reservations for any trains such as from the Kansai Airport to Osaka Station, Kyoto to Narita Airport, etc. ?
3. What is the best way to experience Mt. Fuji with the JRpass? (no skiing, just sightseeing)
4. I read somewhere that we can only take the line from Narita Airport to Tokyo once. Is this true? If so, what are the options for multiple trips? (The hotel we will be staying at is very close to the airport)

Thank you