Not sure what the 156 is - my only thought is it's a special (not the regular flight number for one of them though) or it's one of the new AKL flights that were planned, but may now be a casualty of the cuts.
The C letter in Galileo usually stands for "Closed" class, i.e. no waitlist left, class closed for sale. An R means you have to request a seat in that class to the carrier. The 9's and 0's are as you surmised - 9 or more available or 0 available. Not sure if L is still used, but that is a class that is on waitlist only.