I believe that Kumud is definitely going to be a game changer. She has a very strong personality and knows how and when to use her strong headed-ness. When she can raise her voice at her badi maa, Gumaan doesn't stand a chance.
I am on the fence about Gyaan. Till now I have seen, that even a nominal few seconds of a scene usually has an impact later on. Gyaan was very very upset about whole gua hatya fiasco and also stated that I think I am of no importance in this house. That is one angle to look out for.