Yes, you can play PUBG on Redmi 6.
Yes, Redmi 6 does have the portrait mode.
Yes, Redmi 6 does have a fingerprint scanner. It also supports the face unlock.
Redmi 6 comes with 5W charger.
If your budget absolutely can’t exceed the Rs. 8,000 mark, go with the Redmi 6 without any concerns whatsoever.