It wouldn't take too much to make a breakdown of IP announcements. Ownership is a bit harder to track down, I think.
Looking at something like https://bgp.he.net/AS32934#_prefixes will tell you what IPs Facebook announces. Rinse and repeat for whoever else. Maybe a bit tricky if you need to track down subsidiary ASes.
Disclosure: I worked for WhatsApp including while it was part of Facebook, and was involved in getting AS11917 setup for WhatsApp.
Looking at something like https://bgp.he.net/AS32934#_prefixes will tell you what IPs Facebook announces. Rinse and repeat for whoever else. Maybe a bit tricky if you need to track down subsidiary ASes.
Disclosure: I worked for WhatsApp including while it was part of Facebook, and was involved in getting AS11917 setup for WhatsApp.