14-days JR Pass and 16-day trip

Hi! Hope for help! Thanks in forward!

We are going to Japan in September. We'll buy JR pass for 14 days. But we have 2 days more. And I'm not sure how it more saving to activate passes.

We'll arrive to Narita at Sep 7 in the morning.
I'm planning to go to our hotel near Shibuya st. by Nex. We are going to use Yamanote line to travel around Tokyo
Sep 8 - Kamakura and Yokohama (for fireworks on summer ending)
Sep 9 - Disneyland
Sep 10 - Tokyo
Sep 11 - Tokyo, studio Ghibly museum probably and Odaiba
Sep 12 - Tokyo
Sep 13 - Hakone (we'll buy Hakone Free Pass)
Sep 14 - to Kyoto
Sep 15 - in Kyoto
Sep 16 - 1 day trip to Nara
Sep 17 - 1 day trip to Osaka
Sep 18 - 1 day trip to Kobe
Sep 19 - in Kyoto
Sep 20 - to Tokyo
Sep 21 - in Tokyo
Sep 22 - back home from Narita

May be i should activate passes on arrival and buy one-way tickets for nex on last day. Or may be to buy nex+suica first day and normal tickets to Kamakura and Yokohama. I think suica also will be convinient for subways and buses in our trip

Many thanks! Waiting for answer!