Pneumatics is a term that is derived from the adjective “pneumatic” and describes a collection of things that are pneumatic; it is not, and cannot be pluralized and, as a result, the question is not entirely clear.
Based on the past misuse of this word in a similar manner, you are likely referring to pneumatic cylinders. In this case you are correct that an unlimited number may be used, provided you stay within the weight, sizing, and cost limits.
Alternatively, you could be referring to the Pneumatic storage tanks/ accumulators/ volume chambers. These too are allowed in an unlimited quantity, provided you stay within the weight, sizing, and cost limits. The same is true for pneumatic solenoid valves, however there are a few more restrictions on these that must be considered. If I did not address the component you were referring to, please provide more information so that we can provide better guidance.
The compressor might be the limiting factor. Will you use compressed air faster than you can “make” more? Be sure to figure out how much air volume you need to do the tasks you want.
You are allowed only one compressor. So you are limited to one pneumatic system? Valves are limited by connections on the Crio. You probably run into other constraints first though. The rules do seem a little more open this year though.