In my understanding Kuhu is immature, handling her will be easy for Bigben as she can be easily manipulated.
Handling Mishti is not needed but Mishti will be the fire in Meenus life who will get the secrets out, and make positive changes in everyone's life to destroy the control of Bigben. Abhir will support his wife in every step and there lies the problem for Bigben, she cannot correct or interfere in mishbirs life. Big ben is going to face one strong couple who will be together in their actions.
That also could be very much possible..