Taxi drivers thrives at night as all other modes of transportation is down.
I used to hang out at the roof of my accommodation just looking at the street.. saw taxis passed by every 5-10 mins.. so I assume there will be plenty at the airport.
Just note that it may cost you quite a bit, with the midnight rate and all.

Just look out for the taxi sign and follow it and you come to the taxi queue. Just make sure you know which line to go which is base on destination. But you have 6 people + luggage and this means you might need either a 7 seater of two taxis. So really depends on your luck if a 7 seater appears. At one time I need a 7 seater due to my luggage and it was raining heavily. One of the taxi driver was very nice enough to help me flagged the 7 seater that was far up in the queue.