Add email and name as query args to the success redirect page in OptinMonster.

gistfile1.php

<?php
add_filter( 'optin_monster_conversion_data', 'tgm_om_modify_conversion_data', 10, 2 );
function tgm_om_modify_conversion_data( $data, $object ) {

    // If there is no redirect, do nothing.
    if ( empty( $data['redirect'] ) ) {
        return $data;
    }

    if ( isset( $object->email ) && $object->email ) {
        $data['redirect'] = add_query_arg( 'email', $object->email, $data['redirect'] );
    }

    if ( isset( $object->name ) && $object->name ) {
        $data['redirect'] = add_query_arg( 'name', $object->name, $data['redirect'] );
    }

    return $data;

}