Japan Rail Pass and tips for 20-day trip

Hello,

We are planning a 20-day trip to Japan for 2 people in April 2019.
The planned itinerary is as follows:

Tokyo - 6 days
Kyoto - 4 days
Nara/Osaka - 2 days
Hiroshima/Miyajima - 2 days
Matsue - 2 days
Takayama - 1 day
Kanazawa - 1 day
Tokyo - 2 days

We are considering using a 14-day Japan Rail Pass starting on Day 6 at Tokyo to make our route throughout the itinerary and back to Tokyo.

3 questions:

1- Is this a good itinerary and sufficient time for all of these places for a first visit, or should we reduce the number of stops?
2- Is there a better order to make these stops considering train routes?
3- Is the JRP the best choice for this kind of itinerary, and can we use it for all of the destinations?

Thank you very much in advance,
Marc-André