How to create new key: value items and add them to an existing list?

*This is an Ansible question *

Here is my list:

  userdata.list:
  - ClassType: Full Time
    FirstName: Grace
    LastName: Higgins
    Username: g.higgins
  - ClassType: Part Time
    FirstName: Robert
    LastName: Miller
    Username: robmil
  - ClassType: Flexi
    FirstName: Jeffrey
    LastName: Keller
    Username: jeff.k

I want to append the following values to the existing list, looping for each user:

EmailAddress: {{ Username }} append to '@gmail.com'
OtherAddresses: primary:{{ Username }}@gmail.com,secondary:{{ Username }}@outlook.com
Registered: Yes

Expected output:

  userdata.list:
  - ClassType: Full Time
    FirstName: Grace
    LastName: Higgins
    Username: g.higgins
    EmailAddress: g.higgins@gmail.com
    OtherAddresses: primary:g.higgins@gmail.com,secondary:g.higgins@outlook.com
    Registered: Yes
  - ClassType: Part Time
    FirstName: Robert
    LastName: Miller
    Username: robmil
    EmailAddress: robmil@gmail.com
    OtherAddresses: primary:robmil@gmail.com,secondary:robmil@outlook.com
    Registered: Yes
  - ClassType: Flexi
    FirstName: Jeffrey
    LastName: Keller
    Username: jeff.k
    EmailAddress: jeff.k@gmail.com
    OtherAddresses: primary:jeff.k@gmail.com,secondary:jeff.k@outlook.com
    Registered: Yes

How do I create the dictionary to append the three new key: values, and loop for each user to produce the above output?

This is my current playbook:

- hosts: localhost
  tasks:
    - read_csv:
        path: /var/lib/awx/projects/file/creation.csv
        # key: FirstName 
        fieldnames: FirstName,LastName,ClassType
        delimiter: ','
      register: userdata

    - debug:
        var: userdata.list

Given the mre data

  userdata:
    - Username: g.higgins
    - Username: robmil
    - Username: jeff.k

Use Jinja and create the dictionary update

  update: |
      {% filter from_yaml %}
      {% for user in  userdata|map(attribute='Username') %}
      - EmailAddress: {{ user }}@gmail.com
        OtherAddresses: 'primary:{{ user }}@gmail.com,secondary:{{ user }}@outlook.com'
        Registered: 'Yes'
      {% endfor %}
      {% endfilter %}      

gives

  update:
  - EmailAddress: g.higgins@gmail.com
    OtherAddresses: primary:g.higgins@gmail.com,secondary:g.higgins@outlook.com
    Registered: 'Yes'
  - EmailAddress: robmil@gmail.com
    OtherAddresses: primary:robmil@gmail.com,secondary:robmil@outlook.com
    Registered: 'Yes'
  - EmailAddress: jeff.k@gmail.com
    OtherAddresses: primary:jeff.k@gmail.com,secondary:jeff.k@outlook.com
    Registered: 'Yes'

zip and combine the items of the lists

    - set_fact:
        userdata: "{{ userdata|zip(update)|map('combine') }}"

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Example of a complete mre playbook for testing

shell> cat pb.yml
- hosts: localhost

  vars:

    userdata:
      - Username: g.higgins
      - Username: robmil
      - Username: jeff.k

    update: |
      {% filter from_yaml %}
      {% for user in  userdata|map(attribute='Username') %}
      - EmailAddress: {{ user }}@gmail.com
        OtherAddresses: 'primary:{{ user }}@gmail.com,secondary:{{ user }}@outlook.com'
        Registered: 'Yes'
      {% endfor %}
      {% endfilter %}      

  tasks:

    - debug:
        var: update

    - set_fact:
        userdata: "{{ userdata|zip(update)|map('combine') }}"
    - debug:
        var: userdata

gives

shell> ansible-playbook pb.yml

PLAY [localhost] ******************************************************************************

TASK [debug] **********************************************************************************
ok: [localhost] => 
  update:
  - EmailAddress: g.higgins@gmail.com
    OtherAddresses: primary:g.higgins@gmail.com,secondary:g.higgins@outlook.com
    Registered: 'Yes'
  - EmailAddress: robmil@gmail.com
    OtherAddresses: primary:robmil@gmail.com,secondary:robmil@outlook.com
    Registered: 'Yes'
  - EmailAddress: jeff.k@gmail.com
    OtherAddresses: primary:jeff.k@gmail.com,secondary:jeff.k@outlook.com
    Registered: 'Yes'

TASK [set_fact] *******************************************************************************
ok: [localhost]

TASK [debug] **********************************************************************************
ok: [localhost] => 
  userdata:
  - EmailAddress: g.higgins@gmail.com
    OtherAddresses: primary:g.higgins@gmail.com,secondary:g.higgins@outlook.com
    Registered: 'Yes'
    Username: g.higgins
  - EmailAddress: robmil@gmail.com
    OtherAddresses: primary:robmil@gmail.com,secondary:robmil@outlook.com
    Registered: 'Yes'
    Username: robmil
  - EmailAddress: jeff.k@gmail.com
    OtherAddresses: primary:jeff.k@gmail.com,secondary:jeff.k@outlook.com
    Registered: 'Yes'
    Username: jeff.k

PLAY RECAP ************************************************************************************
localhost: ok=3    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

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