No. Comio S1 does not have the removable battery.
Comio S1 dimensions are 149.2 x 72.6 x 7.9 mm.
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 fingerprint sensor.
Yes, Comio S1 does have the VoLTE support for Airtel.
Good phone. No hanging problem.