No, you need to have a visa, check Hong Kong immigration website

Because the immigration laws were changed in 1965,Asians particularly Vietnamese from Hong Kong, were chosen to come to Canada under refugee status. They later were held in court for a trial, and if their chase was not strong enough to be held as refugee, they were sent back to their refugee camps in Hong Kong

Chinese immigration refers to the movement of Chinese people (eg. people from China and Hong Kong) to another country. For example, there are many Chinese immigrants in British Columbia.

Yes, you can but there are restrictions for some Countries (check with the ferry staff before boarding). If you are arriving in Hong Kong you can get the ferry from the airport direct to Shenzhen- Shekou Port and is not required to go trough the Hong Kong immigration service.

No they are not Hong Kong is not considered part of Mainland China. All people must pass an immigration check point to enter Hong Kong from the Main land and vice-versa. Chinese citizens must also ask permission from the government to go to Hong Kong.