I share your focus on food. We've had quite the incredible visits to Japan, most recently in 2019.
I have to dig up some restaurant names, but one I do remember the we liked very much, was SHIMA STEAK in Tokyo. Very tiny, family-run place. We had lunch there and brought one of their famous steak sandwiches to the Do-me for a baseball game.
One of the best restaurant was one specializing in pork tonkatsu...hidden in an office building and seating about 6 diners at the counter....if you want, I can try to dig up the name. There are entire website devoted to the tonkatsu restaurants in Tokyo..the Japanese take obsession about food to an entirely new level!!
Use Tabelog for restaurant reviews in Japan, and have your hotel make reservations.
https://tabelog.com/en/
Highly recommend going to the Tokyo Dome, even if you do not care much about the game...it's the crowd, and the vendors, that were fascinating. We stayed in the ShangriLa near Tokyo Station and Ii thought that was an excellent area to base oneself. Inside the station there is a riot of small restaurants, so on the nights when we did not book a restaurant, we wandered inside there and had a blast....
In Kyoto, we took advantage of the services of a GoodWill Guide, a volunteer who will craft a plan based on your interests, and accompany you for the day. You pay only for the guide's lunch. Be aware that the English fluency of the guides varies.
https://www.japan.travel/en/plan/list-of-volunteer-guides/
We took a Tokyo food tour with Yukari Sakamoto, Japanese-American woman (her husband was a buyer at Tskujii Market) who has written several respected food guides to Japan; -she took us on a private tour based on our particular interests..
https://about.me/yukarisakamoto
This is her book; highly recommend:
https://www.amazon.com/dp/189214574X?lv=shuf&channelId=500&plpRedirect=mhFallback
For your son,, you must go to Harajuku..enough said.
We also loved the neighborhood where they sell the cookware and those plastic molds of food that some restaurants put on view....
I think you know about the cute animal cafes....devoted to every animal from hedgehogs to capybara....
We went on our own, no tour necessary....we had about a week in each of those two cities; two nights in Kanazawa (forr the gardens) ; and an overnight at an onsen hotel (KAYOTEI) in Yamanaka Onsen; if you can squeeze this in, it's an incredible exprerience.. we chose KAYOTEI because we had a private bath on the terrace of our room, which my partner preferred. All meals are Japanese and no English is spoken so it was quite the experience!!!! Not sure you have time on this trip, but it's an idea I wanted to share because it was so special...
https://blog.bespoke-discovery.com/anniversary-guide-to-kayotei-ryokan-yamanaka-onsen-privacy-and-surprise-design
Recommended book about food: RICE, NOODLE, FISH: DEEP TRAVELS THROUGH JAPANS FOOD CULTURE
You probably know this, but you can send your bags ahead on the train and pick them up at the airport on the day you fly out of Japan..