Taxi from the East Railway Station to the Guangzhou Zoo

I would like to take a taxi from the East Station to the Zoo around 8-9am on a Monday morning. Can my group of five ride in one taxi? (Will two children be treated as one adult for the taxi capacity?) About how long should the trip take? Is there a lot of traffic at that time of day? How much should I expect to pay? Will it be difficult to get a taxi at that time of day? Thank you for your help.