No. Redmi 6 does not have the IR blaster support.
Yes, Redmi 6 does have the 3.5mm headphone jack.
Yes, you can play PUBG on Redmi 6.
You can record up to 1080p resolution videos with Redmi 6.
If your budget absolutely can’t exceed the Rs. 8,000 mark, go with the Redmi 6 without any concerns whatsoever.