Function to dynamically sync CPT team posts with WP users. The post type requires custom meta fields for linked_author (user ID) and email.

wp-team-post-save-link-user.php

<?php
/**
 * Create new users to match team members.
 *
 * @param  integer $post_id Post ID.
 */
function xx_team_post_save_link_user( $post_id ) {

  $user_email = get_post_meta( $post_id, 'email', true );
  $author_id  = (int)get_post_meta( $post_id, 'linked_author', true );

  if( $user_email && !is_email($user_email) ) {
    $user_email = '';
  }

  //No email or author ID, can't proceed
  if( !$user_email && !$author_id ) {
    return;
  }

  // Format first and last names.
  $post_title = get_the_title( $post_id );
  $name_parts = explode( ' ', $post_title, 2 );
  $first_name = $name_parts[0];
  $last_name  = $name_parts[1];

  //We have both an author ID and an email; ensure fields match
  if( $user_email && $author_id ) {
    $user = get_user_by('ID', $author_id);
    $updated_user = [];

    if ( $post_title !== $user->display_name ) {
      $updated_user['display_name'] = $post_title;
    }
    if ( $user_email !== $user->user_email ) {
      $updated_user['user_email'] = $user_email;
    }
    if( $user->first_name !== $first_name ) {
      $updated_user['first_name'] = $first_name;
    }
    if( $user->last_name !== $last_name ) {
      $updated_user['last_name'] = $last_name;
    }

    if( !empty($updated_user) ) {
      $updated_user['ID'] = $author_id;
      $author_id = wp_update_user($updated_user);
    }

    return;
  }

  //We have an author ID, but no email; update the post
  if( $author_id ) {
    $user = get_user_by('ID', $author_id);
    $user_email = $user->user_email;
    update_post_meta($post_id, 'email', $user_email);
  }
  
  //We have no author ID but do have an email; create the user
  if( !$author_id && is_email($user_email) && !email_exists($user_email) ) {

    $username    = $first_name && $last_name ? "$first_name.$last_name" : get_the_title( $post_id );
    
    $author_id = wp_insert_user( [
      'user_login'   => subst(strtolower( $username ), 0, 60),
      'user_pass'    => wp_generate_password(),
      'user_email'   => $user_email,
      'display_name' => get_the_title( $post_id ),
      'first_name'   => $first_name,
      'last_name'    => $last_name,
      'role'         => 'author',
    ] );

    if( is_wp_error($author_id) ) {
      return;
    }

    // Link the post with the new author.
    update_post_meta( $post_id, 'linked_author', $author_id );
    return;
  }
}
add_action( 'save_post_team', 'xx_team_post_save_link_user' );