Booking Shinkansen seats

Hi. I'll be visiting Japan from 25 February to 7 March. I have bought four JR Passes for me and my family, but there has been a delay in delivery, and I haven't received the Fedex parcel yet. We are planning to travel from Tokyo to Kyoto on 26 February (one day after landing in Tokyo), and I am now getting a bit anxious about booking my seats at the Hikari Shinkansen (I wouldn't want to leave it till the last minute). So, my questions are:

1. Is it possible to book the seats before I receive the exchange order?
2. Is it possible to book with the exchange order only, or can I only do it after I exchange it for the actual pass at the airport?
3. Is it possible at all to make online bookings on the Hikari service, or only at your office?
4. What are the odds of not getting 4 seats on the same train if we can only book it one day before?
5. If it takes too long for Fedex to deliver my orders, it might be better to forget about the pass, and buy all tickets individually How can I request a refund? Please bear in mind that I have purchased the Cancellation Protection together with the tickets.

I look forward to your reply. Thank you,

Luiz