Airport to Kunming downtown after midnight

Hi,

My flight lands around 1.30am. There are 7 of us including 3 children. What is the best and reasonably priced way to go downtown?
Public transport?
Airport pickup service from hotel? Is there a market rate?
Flag a taxi from airport ?I think we may need two taxis. Do we need to bargain the fare or will they abide by the fixed fare rate?
Thanks.