Just got back from Japan. The weather there was perfect, apart from the super early sunset at around 4 something It only drizzled like twice over the span of 8 days, with no umbrella needed.

My itinerary was as follows:
Day 1 - Arrived at Narita, took skyliner to get to Tokyo
Day 2 - Hakone
Day 3 - Hakone and back to Tokyo - dinner
Day 4 - Akihabara/Skytree/Boat dinner
Day 5 - Nikko day trip
Day 6 - Odaiba - shinjuku - shibuya
Day 7 - Disneyland
Day 8 - Harajuku - shinjuku for final shopping

Every planning was done by my brother in law as he used to study there way way back

for odaiba you can consider visiting this teamlab borderless. its a digital art museum. it can keep you occupied 3-4 hours.
https://borderless.teamlab.art/

i went to the other exhibition teamlab planets during sept which is also nearby odaiba.

there's a one day pass for odaiba Yurikamome line
Fares
Adult: 820 yen Child: 410 yen

disneyland = disney park with Land theme. You see castle as the center landmark
disneysea = sea based park. The parade show is on the lake/river at the center. Volcano as the center landmark

most people say disneysea is more for adult and disneyland for kids. actually its a lie. Both can be suitable for both adults and kids

disneysea is special at night when the show started

Nikko is currently approaching peak, very nice leaves around the shrines.
Ryuzu Falls up in Okunikko has already shed most of their leaves already.

Nikko itself should be peak next week and there is the Light Up Nikko event at the shrines so you should be good!

But don't really need to bother with Ryuzu, Yudaki, Senjogahara etc coz not much to see already.

I'm currently in Japan now using Travel Recommends Pocket WiFi. Very good coverage . No complains so far. With single full charge, it lasted from morning till night.