Yes, Redmi 6 does have the 18:9 aspect ratio full-screen display.
Yes, Redmi 6 does have the AI face unlock functionality.
If you use the supplied 5W charger, it charges to 18 percent in 30 minutes and 35 percent in an hour.
Redmi 6 is made of industrial grade polycarbonate material.
If your budget absolutely can’t exceed the Rs. 8,000 mark, go with the Redmi 6 without any concerns whatsoever.