You can managed the IAPs using the built-in Virtual controller, this does not require a license. You can manage the IAPs using Aruba Central which will at a minimum require a device license (per AP) and if any additional services such as Guest are required, then a Services (per AP) licenses is required.
The Central datasheet will give you all the info you need if using IAP + Central.
https://www.arubanetworks.com/assets/ds/DS_ArubaCentral.pdf
You can also convert the IAPs to APs and terminate these on a Mobility Controller.