Yes, Nokia 8110 4G is a dual sim mobile phone. You can use one 4G sim card in one slot and another slot will be on the 2G network.
Nokia 8110 4G comes with 512MB RAM and 4GB internal storage. Hence, just like your Android phone, it has phonebook with unlimited storage.
Nokia 8110 is 133.45 mm ( 13.34 cm) long and 49.3 mm ( 4.93 cm ) thick.
Yes, Nokia 8810 4G does have the VoLTE support. You can make calls via VoLTE enabled network easily.