Here is some old idea of mine based off the game EU4 (1444AD): New civlisations for the subcontinent
I am not good at designing tech tree but maybe it can help some nomenclature, hehe.
I would want to see Tamil (classic Dravidian civ), Odia (classic East Aryan civ) and Rajput (the Indians with Camels), one from each corner.
Tamil should have some infantry UU and Navy Bonus.
Odia should have some heavy Elephant bonus or Monk bonus.
Rajputs are just renamed Indians.