We are not sure if the JR pass is the best option for us!!

Hello :) my husband and I are going to Tokyo from the 5th of June 2018 till the 12th of June (8days) and we have some questions regarding the JR PASS and to know if its the best option for us.

1. Does the pass gets activated 7 days exactly beggining at the time I activated it? For example if I activated the 5th at 3:00 pm does it remains active until 3:00 pm 7 days later? or how does this work?

2. We are planning to visit Tokyo with the JR PASS, do you think its going to be enough with the JR Pass metro Lines that are included in the JR PASS? or we are going to need a Suica to move between Tokyo?

3. We are planning to go to Kyoto for 1 Night but we wanted to know if we should reserved the Seats for the Shinkansen trading for the 7th of June till the 8th or how does this works? you always get to sit on these Shinkansen trains?

4. On our last Day (Day #8) we would need to Buy a ticket to go back to Narita airport...which option do you Think is the best and cheapest way to get into the airport for our flight back home?

Thank you very much :)

Gina