Yes, Jio Phone 2 does support the Tamil language.
Yes, you can use WhatsApp in Jio Phone 2.
No. You can use Instagram website but you cannot use the Instagram App on Jio Phone 2.
No. You cannot use the 3G network on Jio Phone 2. You can use the 4G network and 2G network.
Yes, Jio Phone 2 does have the wifi hotspot.