Kindly advice appropriate JR pass

Dear Sir
We are planning to visit Japan as per the following itinerary.
28 March Osaka KIX to Shin Osaka:
29 March Osaka Shin-Osaka to Himeji-Back
30 March Osaka Shin-Osaka to Hiroshima-Miyajima-Back
31 March Osaka +Kyoto Local +Transfer to Kyoto
1 April Kyoto Nara
2 April Kyoto Local
3 April Kyoto Local
4 April Kyoto + Nagoya Transfer to Nagoya
5 April Nagoya Local
6 April Nagoya +Hakone Transfer to Hakone (Odawara)
7 April Hakone+ Tokyo Transfer to Tokyo
8 April Tokyo Nikko day trip
9 April Tokyo Local
10 April Tokyo Hitachi Sea side
11 April Tokyo Local
12 April Depart for Mumbai from Narita

We are proposing to use the JR Kansai Hiroshima pass for 5 days from 28th March to 1st Apr. Request for your advice on the following:
a) Is the JR Kansai Hiroshima pass still valid? If yes, what is the cost of the pass for 5 days?
b) Is there any other pass more appropriate for Kansai region?
c) Is there any other JR pass that could be used for the rest of the itinerary?
d) Which is the most authentic website to buy individual Shinkansen tickets?

Would be grateful for your advice.

Regards
Aslesha