scheduling a Japan Pass

We plan to be in Japan for 12 days in October 2015. Considering we arrive at 9 pm and could use the pass that evening to get into the city, and we depart from NRT at 2 pm 12 days later, (this would count as 13 days usage for the rail pass), and we intend to travel to Kyoto, Hiroshima, and Matsuyama as well as day trips to Kamakura, Nara and Himeji, I'm guessing it would probably be worth buying the 14 day rail pass. Would you agree?
This assumes we will do our own travel arrangements for side trips and not sign up for organized tours. Are we assuming too much to think we two English-only speakers can manage the connections, etc.?

http://www.japan-guide.com/e/e2323.html

Yes, it's worth it. You can manage with only English but I strongly encourage you to learn a few phrases in Japanese to be polite and grateful.

The "right" pass depends on how much time you spend in Tokyo. If you plan to stay in Tokyo for a couple days right after arrival and/or before departure and all your long-distance trips are within 7 days, the 7-day pass will probably be more advantageous.

If you go with a 7-day pass, for your trips around Tokyo you can look into the N'EX direct or round-trip ticket (depending on your dates), the Kanto Area Pass or the Kamakura-Enoshima pass.

A 9PM arrival is too late to exchange your JR Pass voucher for a JR Pass. Think about using the Keisei SKyliner into Tokyo from NRT. It's much faster than the NEX anyway, and cheaper at Y2400. It stops at Nippori where there are sosme business hotels. It's also a great area to spemd some time.
If you get a 7-day pass, plan your trip so on your last day you use the JR Pass to go from Kyoto to Tokyo (Shinagawa Sta.) and then on the NEX to NRT.
Leaving Kyoto around 8:30AM gets you to NRT around noon.

The offices at Narita close at 21:45, that's enough time unless the flight is delayed.

Agree with Firas, I can be out of the plane and at the counter in under 30 minutes including collecting check-in luggage. But it really depends on the immigration at that time.

Thank you for all the informative comments!

It would seem our 8:55 pm arrival time may be a challenge. I have read there is a 1500 yen NEX ticket into Tokyo available to travelers with a foreign passport. Does anyone know if ticket machines have prompts in English? Can one pay with a credit card? a debit card?
We clearly have a lot of research to do to figure out the train system. We appreciate your advice.

The Y1500 one-way ticket will be discontinued in March, but replaced by a round trip for Y4000, a good bargain.