Does IAP continues to communicate with activate after the conversion to Campus AP or Remote AP?
No. Once the IAP gets converted to Campus-AP or Remote-AP, it would not reach to activate.
By design, only IAP firmware is programmed to communicate with activate (using the domain: device.arubanetworks.com). Once the IAP is converted to Campus-AP or Remote-AP, it would download the image from controller and thereby do not talk to activate.