Yes, LG Q6 Plus does have the face recognition. You do not even require to power up your phone. It's camera automatically detects your face and unlocks the phone more quickly than typing, drawing or fingerprinting.
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. You cannot change the color of the notification light in LG Q6 Plus.
Yes, LG Q6 Plus does have the Corning Gorilla Glass.