No. iTel S41 does not gorilla glass but it's display is scratch resistant.
Yes, iTel S41 does have the LED flash with the front camera.
Yes, iTel S41 does have the eye protection mode which reduces strain for long reading.
Yes, iTel S41 is a VoLTE supported phone. You can enjoy Jio video calling easily.
Yes, iTel S41 does have VoLTE support.