No. You can use Instagram website but you cannot use the Instagram App on Jio Phone 2.
Yes, Jio Phone 2 does have the support for the Kannada language.
No. Jio Phone 2 does not have the front camera flash.
Yes, you can use WhatsApp in Jio Phone 2.
Yes, Jio Phone 2 is a dual sim mobile phone. You can use 4G sim card slot with the Jio sim and another slot can be used with 2G network sim card.