I like Rahul - particularly Manish, the actor, so I'm glad he'll be back for the final episodes. Yeah, I was wanting this as well - Rahul to return, and w/ Shaan, help realize Shaan's dream, as well as his own - of having a successful music company. They don't have the time to focus on RaJen, so I'm guessing people won't have to worry about that aspect.
I like the new Adiran jodi, and wish there was more time to show this as well - maybe they can leave while announcing that they're engaged. Similarly, I'd like Puppy & Khusi to end up together too, and someone for Gangubai. Maybe bring in a cameo ex lover to claim her, so that all 3 jodis can stay.
But yeah, I'd like to see a Shanak episode. Maybe have Shanak return home and Kanak discover she is pregnant. For the finale shot, have a party where Kanak's pregnancy is announced, and have the above 3 jodis announce their own engagements.