Taaliyah are currently suspicious that her behaviour is all an act. If Pragya can sell her act to the two people (Sarla and Abhi) who know her better than anyone, then she's achieved her objective.
Taaliyah and Raj are suspicious that Pragya has come back into their lives with a plan -- but they have no idea what that plan is. Pragya making Abhi believe that she is not his Pragya speaks volumes, because he knows her best. And if even he starts believing her act, then everyone will -- Meaning Taaliyah will.
Pragya has to sell her new persona HARDDD. If she does that, then it throws Taaliyah off of her intended mission. If they believe Pragya and Abhi hate each other, then they'll be blind to the fact that she's there to save him - because why would anyone save someone they hate?
Pragya's behaviour is a distraction tactic. She's hiding in plain sight; letting everyone focus on what they see. Pragya is essentially using herself as bait.
Having Abhi buy into the act not only ensures that he stay away from her, but it also makes sure that he continues undeterred with the Tabhi wedding.
The countdown is on for Tanu: Does she want the miserable life that is now in store for her, if she marries Abhi? Because that is the picture Pragya is painting for her -- marry Abhi and this is how things will be: bow down to me always, wear rags, cook and clean and be my slave. Abhi can't protect Tanu, because Pragya has essentially cut him off at the knees.
And as for the Mehra's banding together - sorry, but no. Daadi is there to foil their plans, just like Abhi had been doing originally every time Pragya tried to leave the house. The Mehra's will be unsuccessful in that regard, because of Daadi -- and in the meanwhile Pragya will be putting the pressure on Tanu.
Tanu is her TEAM's weakest link. She'll rat herself out once she realizes she's stuck in an impossible situation. Nikhil was right - she will eventually go running to him herself.
As for Aaliya and Raj -- Pragya's constant insistence that Abhi look into his financial statements is what will have them spooked. Once they know that Abhi is pulling those records - they will have to rush to find a way to put the money they withdrew right back into his account.
I'm not saying everything will tie itself up nicely and be all peaches and cream. Because it won't. The CVs won't be so kind unless the show is approaching it's end. Raj will escape. I'm sure of it. He's to crafty to be caught and Aalu has a history of going down alone and taking full blame upon herself. Also, Abhi will heavily misunderstand Pragya during this track. He fought against everything in him for so long - unbelieving that she had truly changed, but Pragya has succeeded in making him think the worst. This is what we will have to bare. Here is where Pragya will cry endless tears. She'll cry and pray and we'll flich everytime she is forced to play the part of the wretch. But by the end of this charade, Daadi will make everyone see reason and understand that what had to be done was for the best.