00-initialize.php

<?php
/**
 * Initializes the plugin settings fo ruse throughout the rest of the plugin.
 */
private function initialize () {
    $settings = [
        'username' => '',
        'user-info' => [
              'location' => '',
              'id-number' => '',
              'first-name' => '',
              'last-name' => '',
        ],
        'short-bio' => '',
    ];
    update_option('acme-plugin-settings', $settings);
}

01-constructor.php

<?php

/**
 * Intiializes the properties of the class, primarily the array of settings.
 */
public function __construct() {
    if (false === get_option('acme-plugin-settings')) {
        $this->initialize();
    }
    // More to come...
}

02-final-constructor.php

<?php

/**
 * Intiializes the properties of the class, primarily the array of settings.
 */
public function __construct() {
    if (false === get_option('acme-plugin-settings')) {
        $this->initialize();
    }
    $this->settings = get_option('acme-plugin-settings');
}