Yes, Vivo Y81i does have a notch based 6.22-inch display.
Vivo Y81i is made of Aluminum Alloy and industrial grade polycarbonate material.
Vivo Y81i has FunTouch OS which is based on Android 8.1.
No. Vivo Y81i does not have the front camera flash.
Yes, Vivo Y81i does have a dedicated MicroSD card slot.