Yes, Redmi 6 does have the LED notification light.
You can record up to 1080p resolution videos with Redmi 6.
No. Redmi 6 does have a dedicated MicroSD card slot and 2 other slots for SIM cards.
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.