Thank you!
I can only keep on recommending Rose! Since we posted about her quite a few people followed our recommendation and booked tours with her. They all came back raving abou the experience. She´s a gem!
About Hong Kong... we have been there many times so we don´t actually book a guide any more. However, when we booked a guide many years ago it was with www.hellohongkong.com.hk. It was a good tour, so we can recommend them. Otherwise you can try with toursbylocals.com.
As a hotel we can recommend The Kowloon Hotel. Very good location and reasonable rates.
In Nagasaki I would not do a tour at all. Nagasaki is extremely easy to do DIY. Take a taxi or tram to the Peace Museum and Peace Park, take a tram to Chinatown, walk trough Chinatown and up to Glover Gardens and you´ll have a great day. The ship is within just a few minutes walking distance from Glover Gardens. So really easy.
You can also do Hiroshima on your own. However, it is not as easy as Nagasaki. The iconic Hioshima Peace Memorial/Dome and the Museum are must sees. Then I also recommend seeing Myajima. Both can easily be done in one day. If you want to do it with a guide I can recommend trying toursbylocals.co or gowithguide.com (former triplelights).
We did Hiroshima on this cruise:
https://www.travelandcruise.net/travellove_en/Our-Trips/Celebrity-Millennium-Japan/celebrity-millennium-japan.html
The other Japan travelogues are:
https://boards.cruisecritic.com/topic/2970853-celebrity-millennium-japan-10242023-liveish-report/
and
http://www.travelandcruise.net/travellove_en/Our-Trips/HAL-Westerdam-Japan-01/hal-westerdam-japan-01.html