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.
Yes, Jio Phone 2 does have the support for the Oriya language.
No. You can use Instagram website but you cannot use the Instagram App on Jio Phone 2.
Jio Phone 2 does have the 4GB internal memory. Practically, it has unlimited contact book.
No. You cannot use the 3G network on Jio Phone 2. You can use the 4G network and 2G network.