Yes, Nokia 8110 is made of Polycarbonate material, which does not allow power transmission and thus it makes a shockproof mobile phone.
Yes, Nokia 8810 4G does have the VoLTE support. You can make calls via VoLTE enabled network easily.
Yes, Nokia 8110 4G does have the support for the Facebook App.
Nokia 8110 4G runs on KaiOS which does not have the WhatsApp support. Nokia management has updated that they are working on the same but there is no definitive promise made for the same.