No. It is still the WhatsApp server making the request to your website - so you only see the server's IP.
Facebook makes one request and then caches the result. Other servers may not store the result.
Facebook makes one request and then caches the result. Other servers may not store the result.
TL;DR, the app establishes a TLS connection directly between your phone and the site, but routes it through a proxy on Signal's server, thereby hiding your IP without being able to view the URL. I imagine Whatsapp works in a similar fashion