Before Holi, SidNi might come to know Joker's plan to harm Sid. That is when they plan Roshni's death drama because Joker wants Sid separated not Roshni. So Sid death drama won't reveal the Joker but Roshni death drama might. I feel Roshni might be shown "dead" during the Holi celebration. Then she might come back the next day as someone else, maybe a detective to help Sid and DD to find out who "killed" Roshni. Sid shares all that has happened with DD, so now DD is in on the plan. Sid shares his suspicious that it is someone who they know very well as the SMS and MMS he gets seems as this Joker knows everything about him. So much that it can't be anyone from the outside. It has to be someone from the inside. So Roshni (as a detective), Sid and DD come up with a plan to do things that might make Yash (not known to them) speak up and confess. As Misha was tricked into confessing. But that happened in a span of like an episode. This will happen longer. As Yash won't budge quickly.
But we know whatever happens and however it happens. Once, DurNi come to know the truth about Yash, they will be slapping him left and right BIG TIME!!! I want Sam to also join the slapping spree. Yes she is greedy and spoiled but she does not deserve what she got and is getting. I mean RV cheated her and now Yash is cheating her. No girl deserves that treatment.