I feel that sending Mukku to the hostel drama was just so Kalyani can make that video confessing to all the crimes, which can inturn be used by someone to blackmail Malhar for the wedding to Avni. Cause it doesn't make sense that Malhar would agree to marry her otherwise. If he didn't agree for Baapji, he won't agree for Ahir, especially not when Kalyani alive. So without fail, CVS need some blackmail material for OTT drama.
Isn't it Anu who might have actually seen the video. That's why she's doing drama of Mukku being her daughter.
If Anu has had the sense to see and destroy the CD or video, then noone can use it for blackmail..