Vivo Y81i has FunTouch OS which is based on Android 8.1.
Vivo Y81i has 2GB RAM of LPDDR3 type.
No. Vivo Y81i does not have the removable battery.
No. Vivo Y81i does not have the fingerprint scanner but it does support the face unlock.
Vivo Y81i is made of Aluminum Alloy and industrial grade polycarbonate material.