As I get into details, couple of small doubtsFine!
1 While going ttrain reaches Matsumoto at 9.40 and bus to Kamikochi at 10.10. How far is the bus station from.train station? Walkable.? Actually you will take train (not bus) from Matsumoto to Shin-shimashima where you will take bus to Kamikochi. The train is not JR but a private railway Matsumoto Dentetsu. Matsumoto station of Matsumoto Dentetsu is adjascent to the JR Matsumoto station (of course it is walkable).
This is the station map of Matsumoto prrovided by JR East.
https://www.jreast.co.jp/e/stations/e1444.htmlAzusa limited express will arrive in the 1F platform 3 or 4 (I am not sure). There are an elevator and escalater which will take you to the 3rd floor. You must get out from the ticket gate. The (combined) ticket to Kamikochi is sold at the ticket vending machine on the 3rd floor.
To buy and get on the train, please read the explanation by Matsumoto Dentetsu.
https://www.alpico.co.jp/en/travelog/post/getting-to-kamikochi-from-ma...Read "How to buy and reserve a ticket (from Matsumoto to Kamikochi)" section. Skip "By direct bus (National Park Liner)" section since you will travel "By train and bus". The vending machine has touch panel so first choose "English menu" and tap the green tub of "Alpico Discount Ticket" and then "Kamikochi". This is the combination ticket for Matsumoto-(train)-Shin Shimashima-(bus)-Kamikochi.
With the ticket in hand, enter the ticket gate (I'm sorrry I dont know whether you must go throu the manned ticket gate) and walk to the 7th platform on the 1st floor. Most of the tourist will take the bus at Shin-Shimashima (just outside of the train station) so you don't need to worry about the transfer.
2 While coming back from Komikachi to Kanajawa via Shirkawa go. there are too ma ny bus changes ( 4 I think) . Will it be easy to handle especially as we do not speak Japanees. Yes, it is easy. Many foreign tourists are comming to Japan and many of them do not speak or understand Japanese. Though many Japanese do not understand or speak English fluently, we are happy to assist foreign tourists. If you say Hirayu at Kamikochi bus terminal, the Japanese will understand you want to go to Hirayu, since Hirayu in Japanese is also Hirayu. Anyway, Kamikochi, Hirayu, Takayama are rather big bus terminal and many tourists are waiting their bus. You can find English speaking tourists quite easily.
3 Shirkawa go can be seen on our own or we need guide? Also, where and how do we get bus to Kanajawa? Oh, it's Kanazawa, not Kanajawa. By the way, Shirakawa go is a small village along the river and you can enjoy on your own.
https://shirakawa-go.gr.jp/wp/wp-content/uploads/2018/05/332fc38451fc1...I visited some Gassho-dukuri houses such as Wada house, Kanda house, and the observatory (by bus) and the Heritage Museum which has many Gassho Dukuri houses.
https://shirakawa-go.gr.jp/en/faq/5/Shirakawago bus terminal is rather small, but at least it has a roof.
https://www.vill.shirakawa.lg.jp/1469.htmBus from Shirakawago (Ogimachi) to Kanazawa requires reservation.
https://www.nouhibus.co.jp/highwaybus/kanazawa_en/https://japanbusonline.com/en/CourseSearch/11900040002