You can override some template of FOSUserBundle and redirect to the path of LatchBundle. For example:
{# app / Resources / FOSUserBundle / views / Registration / confirmed.html.twig #}
{% extends "FOSUserBundle::layout.html.twig" %}
{% trans_default_domain 'FOSUserBundle' %}
{% block fos_user_content %}
<script type="text/javascript">
window.location = '{{ path('fourcoders_latch_register') }}'
</script>
{% endblock fos_user_content %}
You can make a custom listener too.