15 days itinerary (Tokyo/Alps Region/Nagoya)

Hi all,

My family of 6 will be traveling to Tokyo, Japan Alps Region and Nagoya (from 5 to 20 June 2019).Our rough itinerary is as follow:

Day 1 - Fly into Tokyo (Stay in Shinjuku area)

Day 2 - Sight-seeing in Tokyo

Day 3 - Day trip to Kamakura

Day 4 - Take JR Azusa Express train from Shinjuku to Matsumoto

Day 5 - Sight-seeing in Matsumoto

Day 6 - Tateyama Alpine Route (take JR Oito Line from Matsumoto to Shinano Omachi Station, followed by bus to Ogizawa Station). Send luggage to hotel in Toyama and overnight in Toyama.

Day 7 - Sight-seeing in Toyama (Visit Tullip Gallery, Castle)

Day 8 - Take Shinkansen from Toyama to Kanazawa.

Day 9 - Sight-seeing in Kanazawa (visit garden, fish market)

Day 10 - Take bus from Kanazawa to Shirakawago (store luggage at bus terminal) and proceed to Takayama after touring Shirakawago

Day 11 - Sight-seeing in Takayama

Day 12 - Take bus to Nagoya from Takayama

Day 13 - Day trip to Kiso Valley

Day 14 - Day trip to Nabana no Sato and Mitsui Outlet Park

Day 15 - Take Shinkansen back to Tokyo

Day 16 - Fly out of Tokyo

Questions
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1) Is the above itinerary feasible?
2) What kind of train pass is recommended? And for how many day? We have 3 adults, 1 kid (age 6 years old) & 2 elderly (> 70 years old). Any discount on train ticket for children and the elderly?
3) Are we able to see tullips in Toyama Tullips Gallery and flowers in Nabana no Sato in June?
4) Any recommendation for ryokan with onsen along route in our itinerary?
5) On day 10 (visit to Shirakawago), we are thinking of spending a night in the Gassho-Zukuri. Any recommendation?
6) Any specific "must visit" attractions to recommend along the route in our itinerary?

All suggestions are most welcome.

Please help.

Cheers :)