This article help you to find virtualization type of an Instance and AMI. I used awscli commands to demonstrate. The same details can be obtained from console too.
Each AWS instance comes with one primary private IP address assigned to first network interface named eth0. This primary IP address will remains unchanged throughout the life-cycle of that instance. AWS also allows assigning multiple secondary private IP address for same network interface. Re-allocating or Reassigning secondary addresses can be done straight away either through console or CLI.