6-day Tokyo itinerary, visiting for the first time. What do you think?

I'll be in Tokyo with some friends from 28th Oct to 3rd November. I'll be staying close to the Shinjuku station. Note that before Tokyo, I'd already have visited Fukushima, Hiroshima, Miyajima, Kyoto and Osaka, and seen most of the popular tourist attractions there already. So with Tokyo I'm meaning to see just Tokyo, and not Japan – if you know what I mean.

My itinerary looks like this –

Day 1 (28 Oct)

1. Arrive in Tokyo early morning via train from Osaka
2. Yoyogi park and Hachiko memorial statue
3. Shibuya scramble crossing (I just have to do it haha)
4. Shibuya sky
5. Cover stores in Shibuya area
6. Dinner (where should I go?)
7. An underground concert (I've heard the underground music scene is really cool in Tokyo, idk which ones to go for, suggestions welcome!)

Day 2 (29 Oct)

1. Tsukiji market
2. Imperial palace
3. Akihabara (non negotiable)
4. Shopping at Don Quixote
5. Bar hopping in the same area

Day 3 (30 Oct)

1. Day trip to Mount Fuji (5-lakes)
2. Kawaguchi lake, Oishi park
3. Some fine-dining experience back in Shibuya or Shinjuku

Day 4 (31 Oct)

1. Minato city
2. Teamlabs Planets
3. Tokyo tower (gaming inside + general sightseeing)
4. Golden gai for goofy pictures
5. Roppongi district
6. Bar hopping in Shinjuku

Day 5 (1 Nov)

1. Senso ji temple
2. Shopping in Harajuku
3. Tokyo skytree

Day 6 (2 Nov)

1. Nezu shrine
2. Ame Yokocho
3. Sleep early for flight back home next day

I'd love to know your opinion on this. I also have these specific questions –

1. Where should I eat if I want a good fine-dining experience? I'm ready to splurge some money. I'll be checking the michelin-guide of course, but would also love some opinions and stories from people here.
2. Is there something that's a must-do for Tokyo, that I'm missing in this itinerary?
3. Are there any days here where you think I'm doing too much? Or are there days where I'm doing too little?
4. Is a trip to Yokohama worth it? If so, I'd have to cancel everything on one of the days above – which day should I cancel?
5. I'll be in Tokyo during Halloween, and I've heard very cool things about Halloween in Shibuya. But I also heard it's not gonna happen this year. Is that true? Is there anything special I can do in Tokyo on Halloween?

TIA!