You know what I feel? So I have always felt that Avni has loved Ahir. Cause even now she keeps saying mera Ahir and I hate Moksh cause he separated me from Ahir.
So right from beginning, I have felt this was an Ahir and Avni plan. Ahir didn't care about Avni, he just wanted his money and badla. But seems like Avni loved Ahir. So I also feel like she hated Malhar and just tolerated him cause she wanted her and her kid to inherit all the Rane money and property. So I feel like her eventual plan was to always kill Malhar. So till the time he hated Kalyani and Moksh was not found, I feel like she still left she could use Malhar's anger for Kalyani and Kaka's hatred for Kalyani to separate KalMa and get married to Malhar. But after KalMa reunited and all was good, she felt like she had no chance.
Malhar, I don't think he knows her truth past what she tried to do to Kalyani when he was presumed dead. Cause if she was that dangerous and he knew it, he wouldn't have let Kalyani and Moksh stay with her for all this time with out making an appearance.
I feel when Kalyani called the police, they told him about the wedding as this entire thing is a police mission. And he went to rescue her and keep her safe. But then he figured out how bad things have gotten at home so he came with her pretending to be Malhar. But pretending in a way that is confusing everyone.