No. Comio S1 does not the face recognition ability.
Comio S1 is equipped with latest Android 7.0 Nougat.
Yes, Comio S1 does have a hybrid sim slot. You can either use 2 sim cards or 1 sim card & 1 MicroSD card.
Yes, Comio S1 does have the VoLTE support for Airtel.