Yes, you can use it. But at any given time, one sim will work on 4G network and another will work in 3G network.
Yes, Micromax Bharat 4 does have the front camera flash.
No. Micromax Bharat 4 does not have the gorilla glass protection but it does have the full lamination technology.
Yes, you can use the Jio sim card in Micromax Bharat 4.
Yes, Micromax Bharat 4 has a removable battery.