I agree they were behind most of the bad happenings.But Sadhana not liying for Ranveer at court.Vasu throwing Sadhana out and trying to get Alekh remarried and Raagini blaming Sadhana for her miscarriage which were the direct reasons of things that happened.All these things were caused by the characters themselves.Just because we have bigger culprits does not mean these things should be excused.
My point is when the sons(Alekh and Ranveeer) realized Naveen and Avni were behind the mishappenings they totally felt sorry for their mother and said they misunderstood her.That is not totally true.Vasu was not innocent of lot of things she caused !How can they portray her so innocent after all the things that happened?