Surprisingly annoying use of conditionals and variables with ec2 instances and volumes. The ec2 module can comfortably create volumes that have controlled delete_on_termination flags but you must first provision the instance and the volume before you are able to tag the volume. Assuming you wanted to tag a single volume based on its device_name …

mysql.yml

---
data_volume:
- name: mysql-data-drive
  device_name: /dev/sdb
  device_type: gp2
  volume_size: 500
  delete_on_termination: false

provision-mysql-aws-volume-nightmare.yml

---
vars_files:
  - vars/secure-aws.yml
  - vars/default-aws.yml
  - vars/mysql.yml
  
- name: Launch mysql instance
  ec2:
    region: "{{ ec2_region }}"
    ec2_access_key: "{{ ec2_access_key }}"
    ec2_secret_key: "{{ ec2_secret_key }}"
    keypair: "{{ ec2_keypair }}"
    instance_type: t2.large
    image: "{{ ec2_image }}"
    instance_tags:
       Name: mysql
       Hosting: mysql-db
       Application: mysql-db
       Hostname: mysql-db
       Expiry: november-2016
       Owner: pavgup
    volumes: "{{ data_volume }}"
    exact_count: 1
    count_tag:
       Name: mysql
    group: ['default', 'mysql-ssh-inside-vpc', 'zabbix-sg']
    wait: true
  register: ec2_mysql

- debug: var=ec2_mysql

- name: grab the just-created volume information for tagging
  ec2_vol:
    instance: "{{ item.id }}"
    region: "{{ ec2_region }}"
    state: list
  with_items: ec2_mysql.tagged_instances
  register: ec2_vol

- debug: var=ec2_vol.results[0].volumes[0]
- debug: var=data_volume
- debug: var=data_volume[0].device_name

- name: tag the volumes that match the data volume size
  ec2_tag:
    resource: "{{ item.1.id  }}"
    region: "{{ ec2_region }}"
    state: present
    tags:
      Name: "{{ data_volume[0].name }}"
  with_subelements:
    - ec2_vol.results
    - volumes
  when: '"{{item.1.attachment_set.device}}" == "{{data_volume[0].device_name}}"'

This was great, thanks so much. the examples on ansible doc were missing some crucial information. For anyone who has multiple volumes, remove the conditional statement and you should be set.