In Shunde Port, you can't go to 200 yuan alone. It takes less than two hours to get to the China-Hong Kong pier. The early boat seems to be 8 o'clock, so shopping is very convenient.
As a matter of fact, it's very convenient to take a bus. In the New World, Fu Ying has a direct bus. It only costs seventy or eighty yuan. You must get off and go through customs. I remember Huanggang and Shenzhen Bay are co-located, and it's not too much trouble. If there is no traffic jam on holidays and there are not many people passing through customs, it will take three hours.
2. Buy an Octopus card, which is convenient for shopping or riding. Return it before you leave Hong Kong. Just get the rest of the money and deposit back.
3. Mong Kok. Any subway station in Tsim Sha Tsui will do.
4. Yes, it needs to be re-endorsed.