Yes, Redmi 6 does have the portrait mode.
Yes, Redmi 6 does have the AI face unlock functionality.
Yes, you can play PUBG on Redmi 6.
No. Redmi 6 does not have the IR blaster support.
If your budget absolutely can’t exceed the Rs. 8,000 mark, go with the Redmi 6 without any concerns whatsoever.