Sulo asks her to get ready fast.
But her answer is 'I would finish up fast and come Aai'. So she could be talking to her mother on phone.

Purvi is happy and ready to get married. Take a note of the forehead and also the side parting of the hair.

Girl Arjun is marrying from the side, does look like Purvi

Forehead looks like Ovi's, very different from the forehead of Purvi in the above pic.
This girl also seems to have side parting of the hair as well. Not very clear in the pic, but does look like it in the video. Bumpy forehead is Ovi's. Purvi's forehead is flatter. And definitely not Punni.

Archana is in the same saree she wore for DK's party. But she has a tear in the eye. This shot might have been taken the day they shot the DK's party episode, but in that episode she did not cry with this kind of expression, I believe. So, they got this expression from her just for the promo.

Manav's face is also more confused and sad than of shock

Arjun is going through the wedding knowing fully well whom he is marrying. He is sad but not shocked.