buying tickets and booking tickets

hi there

we are going to Japan in May
Me, my wife and our baby, we live in China. As we are Brazilian, we had to apply for Visa in the Japan consulate in China. My father in law is going with us. As he still leaves in Brazil, he appplied for the Visa in Brazil

questions`
1- can I buy the 3 tickets, for adults, and ask to deliver in China, or necessary to buy 2 to deliver in China, and 1 to deliver in Brazil?
2 - do I have to buy ticket for a baby (1y and 6 months old)?
3 - we will arive in Narita, and go straight to Kyoto. On the other days, we plan to go to Nara and Hiroshima, stay some days in Tokyo, and then, back to China. Can I use JRP in these locations?
4 and finally (sorry for all these questions), I still not understanding how do I book the trains with JRPass. For instance, after I arrive in Narita, and already going to Kyoto, shouldn´t I book the train in advance?

Thank you for your assistance and patience

best regards