Nokia 8110 4G comes with 512MB RAM and 4GB internal storage. Hence, just like your Android phone, it has phonebook with unlimited storage.
No. Exactly we cannot say that Nokia 8110 4G is a waterproof device. But it is IP52 certified. Means it is splash proof. You are protected up to some extent by water.
Yes, Nokia 8110 4G does have the support for the Facebook App.
Yes, Nokia 8110 4G does have the GPS support.