14d in Japan

We would like to know if JR pass would be cheaper for us, and we would like to know when is the best time to use it. We're planning on buying 7d pass but not sure if the cost is worth it since we're not going back to osaka to fly out.

Passengers: 6 Adults. 2 Childs (Below 5 Years Old)

Day 1: Arrive in Osaka (KIX Airport)
Day 2-3: Osaka Tour, Universal Studios
Day 4: Osaka to Nara
Day 5: Osaka to Kyoto
Day 6-8: Kyoto Tour
Day 9: Kyoto to Tokyo
Day 10-12: Disneyland, Tokyo Tours
Day 13: Nikko
Day 14: Departure Tokyo (Narita Airport)

Please help us decide, we appreciate your help! Thank you!