should i buy 14 or 21 day pass

Hi there,
we are a party of 5 and are arriving on Tokyo on the 28th of December
we are staying:
6 nights in Tokyo 1n Odawara
4n Kyoto
4n Osaka
2n Hiroshima
3n Seoul
1n Tokyo

Question1: I am unsure whether to buy a 14 day pass plus a one way narita express and separate Tokyo city transport option OR
whether to just buy the 21 day pass (although we will have wasted days whilst we are in Seoul)

Question 2: Wwe want to explore the Hakone region for 2 days, ie. the cable car, ropeway and lake. But the Hakone pass seems to be expensive and covers some of the same things our JR pass will include. Do you have any recommendations to this part of our trip.

Any help would be great, thank you
Jay Page