So Mehra mansion is a lavish bungalow. It is the home of rockstar. Fine.
First of all, they have a bunch of people that are rockstar's relatives, staying in the house. Immediately relatives is fine but his cousins, their families uncle and aunty also occupy it. Okay joint family-fine.
But even his Daadi's sisters (Daasis) end up in the house staying forever leaving behind their families.
All these family characters are needed to drive some comic relief, for giving out shocked expressions when the main characters go through some issues and yeah to gossip and stay in the background! At times some of them are used to move plots!
The name of the soap is Kumkum Bhagya and that's a marriage hall belonging to Sarla Arora. Although she runs a marriage hall, all of her younger daughters' marriage events happen in the Mehra mansion. I am pretty sure the marriage hall itself might be more convenient for marriage events than the rockstar's mansion but for plot purposes such as having Aaliyah arrange kidnapping or murders, Mehra mansion is surely convenient- that's where she lives! Of course the rockstar is generous but weird that Sarla Maa would agree to his offer and decides to get Bulbul married in her first daughter's 'sasural'.
And then Tannu! She claims to be a super model but more or less a permanent resident of Mehra Mansion so far. Pragya makes it official by bringing her into the house even before TaBhi marry, so that the CVs can deliver TaBhiGya scenes! Even after her parents take her away learning of her pregnancy and Abhi being still married to Pragya but she comes right back in there. Her parents do not want to host her wedding to Abhi in their home nor do they want to attend her mehendi celebrations which is again hosted in Mehra mansion. Now Tannu will continue to stay in the mansion despite Pragya occupying and ruling over it while she can have a breather in her home or her parents'!
And Abhi and Pragya are also kept in the Mehra mansion with convincing and sometimes not so convincing reasons! Abhi and Pragya leave the mansion due to issues but get right back in with their own reason in the very next episode! Now Pragya claims she is divorced from Abhi, and to have snatched the property but then she is also staying in the mansion with everyone else. Not only she is staying in the mansion but in Abhi's room! So this is her ex-husband that supposedly cheated on her and his marriage to his girlfriend is around the corner too! But she will share the room with Abhi and no one will mind (I know both AbhiGya want each other so they won't mind). Tannu, Abhi's elders or Pragya's elders have no issues whatsoever with AbhiGya still in one room. Otherwise they are people who mind lot of things!!
So basically Mehra mansion and its rooms get used in KB with wired logic and purposes to have characters under one roof and churn out drama after drama!
Long live Mehra mansion!
😆