Was southern India a feudal society like in Europe and Japan, or was it a more centralized unitary system with local magistrates directly adminstering regions for the empire like in Yuan and Song China? The empire broke the dynastic monopolies that had existed for over a millennium like the Cholas and Cheras, how did they play into things?
While you wait for a more comprehensive answer, perhaps this answer I gave a while back to a tangentially related question regarding the structure of the military of Vijayanagar might help answer some parts of your question.