Welcome Churri to the SNS forum, I'm Nafisa.
I don't think the new girl is Anita, though your storyline is how we all guessed the relationship of Gohem to go prior to seeing the promo of the new girl.
In the promo there are some clues...She walks up to the door, rings the bell with her "mid length" "pink" dress and Aham says Tum and Gopi and Rashi are puzzled.
I'm remembering during Kinjal's track when we heard from Radhika Aunty from the US who said that Kinjal couldn't visit with them afterall as she was pregnant and they have daughter-in-laws and daughters in that house it will be shameful for them to see Kinjal in that way, they might get ideas and become loose too...😳, anyway the point I'm making is Radhika Aunty's daughter has arrived in India for her vacation. Modern type girl (well modernish), decided to cut a ticket climb a plane without informing them before hand (very bad manners) and turn up there.
Aham knows her possibly because when he was doing his MBA abroad he lived with her family or met her then, or possibly just through weddings or videos and pictures, or previous visits to India.
Also Anita the times we saw her she wore mini dresses and not mid length dresses, and never chose them in pink of all colours. Also this new girl's hair is dark whilst Anita's hair was lighter. I'm not saying if Anita's introduced they won't bring a new actress but they would stay in character with the colour of the hair and style of clothes. Also why would Anita bring a suitcase with her to come stay at the Modi bhavan (this is a strong clue that the new girl is not Anita), when they have a house of their own in India, or she would go stay with her friends she would know that Kokila doesn't like her, she would not be welcomed to stay in the house, even for a short visit, so I think this is a relative from abroad rather then Anita.