Green vs ordinary and reservatiins

Hello Daniel-san,

Our upcoming trip is in November. Four adults and two children. I understand the ordinary pass is easiest as you don’t necessarily need to make reservations. However, we are travelling a few days during the Nov public holiday and the weekend that follows.

1). Is that a very busy travel time and are reservations usually necessary then?

2). How far ahead would reservations need to be made?

3). Travelling with children 8 and 10. Is green car frowned upon with kids?

4). Can all reservations be made at a ticket machine or must you go to the JR office?

5). How inconvenient is it to make the reservations? Are lines usually long?

6). With Green pass, are you able to go in the ordinary unreserved cars?

7). Is there any way to book online once in Japan? Route is between Tokyo and Hiroshima and return.

Thank you very much for your assistance, as always.