Kyoto to Narita Airport

Hi, I have few questions here...

We are leaving Japan from Narita Airport on 22 Oct morning, therefore planning to the night transit plan from Kyoto to Tokyo.

If we taking the night train, LTD.EXP SUNRISE SETO or LTD.EXP SUNRISE IZUMO
, how to book the nobinobi compartments which covered by the JR pass?

By the way, what is the difference of SUNRISE SETO and SUNRISE IZUMO?

Otherwise, if taking the night bus, which routes and how to do the reservation?

This is our 1st trip to Japan, and would really need some advice of how to go about. The main concerns is not missed the morning flight...

Night bus is available from JR Kyoto Station(22:15) to Narita Airport(06:50). One bus per night.

If we taking the night train, LTD.EXP SUNRISE SETO or LTD.EXP SUNRISE IZUMO
, how to book the nobinobi compartments which covered by the JR pass?

At a ticket counter of a JR railway station. But note that the train does not stop in Kyoto. You would have to backtrack to Osaka and catch it from there.

By the way, what is the difference of SUNRISE SETO and SUNRISE IZUMO?

The Seto travels between Tokyo and Takamatsu. And the Izumo between Tokyo and Izumo. They travel together as one train between Tokyo and Okayama.

Otherwise, if taking the night bus, which routes and how to do the reservation?

See above post. Reservations for that particular bus can be made by phone (06-6643-1007, possibly no service in English). Or through convenience stores (basic Japanese reading skills required - or the help of a Japanese person, such as the store's staff) or over the internet (Japanese only):
http://www.nankaibus.jp/express/09/

There are dozens of additional buses that operate between Kyoto and Tokyo, but you will have to arrive in Tokyo at least 4-5 hours before the departure of your flight. One of them has an English online reservation system:
http://willerexpress.com/