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.
Ubuntu package manager has multiple tools to list the available package updates for installed deb packages. Look into all options and choose the one which you feel comfort. Among given options, first two option are my favourite. Because they populate list of available package updates with version details.
The one who new to Ubuntu like me may face difficulty in understanding grub.cfg. But making Ubuntu to boot into older or previous kernel version is really simple. The configuration is same like Redht except small change in syntax.
Ansible can report execution time for each task. And total time taken for playbook execution. It is more useful to estimate the time of completion as specially for long running jobs.