gistfile1.txt

- hosts: all
  tasks:
  - include_vars: "variables/adminusers.yml"
  - include_vars: "variables/delusers.yml"
  - name: Remove users
    user:
      name: "{{ item.name }}"
#      uid: "{{ item.uid }}"
      state: absent
      remove: yes
    with_items: "{{ delusers }}"
  - name: Create admin users
    user:
      name: "{{ item.name }}"
      password: "{{ item.pass }}"
      uid: "{{ item.uid }}"
      group: users
      shell: "{{ item.shell }}"
      state: present
      groups: sudo
      home: "{{ item.home }}"
      createhome: yes
    with_items: "{{ admins }}"
  - name: Add SSH keys
    authorized_key:
      user: "{{ item.0.name }}"
      state: present
      manage_dir: yes
      key: "{{ item.1 }}"
    with_subelements:
        - "{{ admins }}"
        - authorized_keys

so I would....

1. create host_vars and group_vars dirs in the same location as your playbook
2. in group_vars/all I'd have
   home_root: /home
3. in host_vars/SOMEHOST I'd have
   home_root: /someotherhome

and then in your variables files, wherever it says home:

admins:
- name: username
home: "{{ home_root|default('/home') }}/username
...