Narita Airport to Hiroshima

Hi, Ive decided to travel to Japan Next March for 14 days. I will be travelling to Tokyo, Kyoto, Osaka, Himeji, Hiroshima. I am not buying an open jaw ticket due to my budget, So I am thinking of Flying to Narita Airport from Singapore and will reach Narita Airport at about 7am in the morning. Then straight away, I will take the Shinkansen from Narita Airport to Hiroshima and then start my tour by travelling backwards from Hiroshima to Osaka to Kyoto and final stop Tokyo so I can fly back from Tokyo Narita Airport to Singapore. My questions:

1) What time does the JR pass office open in Narita Airport?

2) How do I travel by Shinkansen from Narita Airport to Hiroshima? Where do I go to take the shinkansen (Train), at which station from Narita?

3) How long does it take to travel by Shinkansen from Narita Airport to Hiroshima?

4) Will my JR pass cover the trip from Narita Airport to Hiroshima?

5) Can I do a day trip to Osaka and Himeji from Kyoto?Basically I only want to go to Universal Studio in Osaka and to see the Himeji castle. Is one day enough? Frankly speaking, I do not really want to stay in Osaka, I rather do a day trip.

6) Can I exhange my JR pass on the 3rd day stay in japan just in case I want to change my travel plan? Does that mean I have to travel back to the Airport and exchange my JR pass? Or can I choose a date to activate my JR pass upon arrival at Narita Airport so I do not have to travel back to the airport to activate my JR pass...

Ive read the website of the JR pass but dont really understand, so hope to get some help here, thanks!!^_^ Cheers!!!!!!

1) The ticket office opens at 6:30 AM.

2,3,4) With the rail pass, you'll end up taking three trains: the Narita Express (N'EX) from the airport to Tokyo or Shinagawa Station, then a Hikari shinkansen train to Shin-Osaka, and finally a second Hikari train to Hiroshima. The whole trip will take a little over 6 hours!

Use this website to check the schedule information:
http://grace.hyperdia.com/cgi-english/hyperWeb.cgi
Your starting station is "Narita Airport" if you're arriving at Terminal 1, and "Airport Terminal 2" otherwise. Under "route to choose", be sure to select the Except Nozomi option. (You can't take Nozomi trains with the JRP.)

6) When you exchange your order for the rail pass, it doesn't need to start immediately - you can choose any starting date within 30 days. You can also exchange it at most major JR stations, including Hiroshima, Osaka, Shin-Osaka, Kyoto.... no need to go back to the airport! Here's a list of all the stations where you can exchange the order:
http://japanrailpass.net/eng/en009.html

Hi Nicholas, Thanks alot for your help^_^ Now i may change my plan because it takes about 6hrs to travel from Narita to Hiroshima.. a little bit too tiring because I will be in the plane for about 7 hours from Singapore to Tokyo already, hmmm... dont really think want to continue another 6 hrs of travelling after I touched down in Tokyo Narita. So I may be spilting up my trip to Tokyo. I may stay in Tokyo for the first 2 days, then get my JR pass activated on the 3rd day and I will start travelling to Hiroshima and then travel backwards and back to Tokyo. I want to end my trip in Tokyo Disneyland. Once again thanks Nicholas for your help^_^ Cheers!!