Yes, Jio Phone 2 does have the Gujarati language support.
Yes, you can use WhatsApp in Jio Phone 2.
Yes, Jio Phone 2 comes with the pre-loaded Facebook application.
No. You cannot use the 3G network on Jio Phone 2. You can use the 4G network and 2G network.
No. Jio Phone 2 does not have the front camera flash.