In Pandiarajan's debut movie as Director 'Aan Paavam', what is unique about each character's name?

Their character names were all their own names!

V.K.Ramasamy - Ramasamy
Paandian - Periya Paandi
Paandiarajan - Chinna Paandi
'Poornam' Viswanathan - Viswanathan 'Vaadiyar'
Janakaraj - Kanakaraj
Seetha and Revathi were Seetha and Revathi