13 days trip-use of JRP

Hello,

we are planning a trip to Japan 2nd-15th June. The itinerary would be as below:

2nd of June: arriving at Narita airport and going to Tokyo Station (our hotel is in Ginza)
2nd-4th June: staying in Tokyo
5th June: trip day in Kamakura--> tokyo-kamakura round trip
6th June: trip day in Nikko -->tokyo-Nikko Round trip
7th June: Kanazawa -->Tokyo-Kanazawa one way trip
8th June: stop in Shirakawago in the morning and then going to Takayama -->Kanazawa-Shirakawago-Takayama (I think this can be done just with bus)
9th June: Takayama-Kyoto one way trip
9th-10th June staying in Kyoto
11th June: day trip Uji -->Kyoto-Uji round trip
12th June: Osaka day trip--> Kyoto-Osaka round trip
13th June: Nara day trip --> Kyoto-Nara round trip
13th June at night: Kyoto-Tokyo --> Kyoto-Tokyo one way trip
14th June: Tokyo
15th June Tokyo-Narita airport one way trip

Is it more convenient to buy a 14 days JRP or to buy a 7 days JRP and pay the remaining tickets separately?

Does the JRP covers all our trips (with the exception of the trips Kanazawa-Shirakawago-Takayama)?

Also, is it possible to book the seats on the trains covered by the JRP online or can this be done just in the JR ticket offices?

Thank you in advance for your help and suggestions

Best regards

Benedetta