Bus from shantou to Guangzhou: around 6 hours;
to Zhuhai:6-7 hours;
No direct bus from shantou to Macau, you need to go to Gongbei Port in zhuhai(about 7 hours)first, then pass the port to Macau.

Train from shantou to Guangzhou: 7 or 8 hours.
No direct train from shantou to zhuhai and Macau.

Change of plans. We arrive in Zhuhai and visit Guangzhou. Long distance bus - how many hours and do you have 1st class seats?

You mean from Zhuhai to Guangzhou by long-distance bus? It takes about 2-2.5 hours. I have not heard that this site have bus ticket booking service. You can buy the ticket at the bus station and the first-class ticket is around rmb50. Remember to take the public-owned buses, for those private buses will not go on highways and the journey will take as long as 4 hours.