Yes, LG Q6 Plus does have the ViLTE support and you can make video calls.
LG Q6 Plus has 3000 mAh Li-Ion battery which offers talk time of about 16 hours and standby time of about 200 hours.
No. LG Q6 Plus is not a water-resistant phone but it is made of incredibly strong 7000 series aluminium.
Yes, LG G6 Plus does have the NFC sensor.