Yes, Vivo Y81i does have the virtual gyroscope sensor.
Vivo Y81i has 2GB RAM of LPDDR3 type.
No. Vivo Y81i does not come with the earphone in the box. You have to purchase it separately.
No. Vivo Y81i does not have the front camera flash.
Vivo Y81i comes with 5V / 1A charger. It does not support the fast charging.