Hong Kong to Guangzhou

My family is going to catch a high speed train from West Kowloon station to Guangzhou and we are going to stay at Mandarin Oriental Guangzhou. Which station is closer to the Hotel - Guangzhou East Station or Guangzhou South Station?
Besides, which is the most suitable train we should catch if our flight lands at around 2pm and how much will it cost for Business Class and First Class fares? Where can we purchase the tickets?
regards,