How to get user-meta from Social Login registered users?

It looks like social login plugins (such as WordPress Social Login, OneAll etc.) do not create users in the original wp-database as regular registration from Admin dashboard. Hence it is not possible to add or get user-meta-data from current user the ‘normal way’.

Question is: How to get user-meta from Social Login registered users?

I have a current case, and have not yet found he answer. Hope you can help me out.

The case
In this case we have a Gravityform which allows registered users to submit a new page. We want them to submit only one page per user. Page title is auto created and do have the form entry-ID as unique part of page title (Gravityforms settings). This function below is used to make Gravityforms to create a page instead of a post:

add_filter("gform_post_data", "change_post_type", 10, 2);
function change_post_type($post_data, $form){
    //only change post type on form id 1
    if($form["id"] != 2)
       return $post_data;

    $post_data["post_type"] = "page";
    return $post_data;
}

Now we want users who have completed the form successfully and are currently logged in, to show the url of their created page like www.example.com/pagenumber{entry-ID}
Therefore there are 3 options what to display:

1. user is logged in and have created a page -> show page url
2. user is logged in and have not yet created a page -> show form -> redirect to point 1 after completing
3. user is not logged in -> show social login buttons -> redirect to point 2 after connecting

First we need to add the form entry ID to the user-meta:

add_action( 'gform_after_submission', 'wpse96480_map_user_to_page', 10, 2);

    function wpse96480_map_user_page( $entry, $form ) {
        $user_id = $entry['created_by'];
        $meta_key = 'generated_page_id';
        $meta_value = $entry['post_id'];
        $unique = true;
        add_user_meta( $user_id, $meta_key, $meta_value, $unique );
    }

Now we add the code below to the page.php (or page template file) to check if current user is logged in and have an entry-ID in user-meta, and if so, to display the url with the entry-ID:

<?php
    if ( is_user_logged_in() ) {
        global $current_user;
        // $current_user = get_currentuserinfo();
        $user_id = $current_user->ID;
        $meta_key = 'gform_entry_id';
        $single = true;
        $entry_id = get_user_meta( $user_id, $meta_key, $single );
        if( strlen( $entry_id ) > 0 && is_numeric( $entry_id ) ) {
            // we have an entry ID now
            ?>
            <h2>Hey <?php echo $current_user->display_name ?>, thank you for submitting the form. Visit your page here: www.example.com/pagenumber<?php echo( $entry_id ); ?></h2>
            <?php
        } else {
            // we don't have an entry ID for this user
            ?>
            <h2>Hey <?php echo $current_user->display_name ?>, Thank you for joining. To create a page please submit the form below:</h2><?php echo do_shortcode('[gravityform id="2" name="just a form" title="false" description="false"]'); ?>
            <?php
        }
    } else {
        // user is not logged in
        ?>
        <h2><Please log in to create a page <?php do_action( 'wordpress_social_login' ); ?></h2>
        <?php
    }
?>

The result:
If a regular registered WP user (who is created by Admin in the Admin dashboard) is logged in, and completes the form successful, option (1) is effective/successful showing as we wanted. If user have not completed the form yet, option (2) is effective/successful showing.

The problem with Social Login users:
If a user registered via a Social Login Plugin is logged in, and have completed the form successful, option (2) is still showing like user has never completed the form.

Question:
How to get user-meta from Social Login registered users?**