If I purchase a resale flat in a society from the nominee after death of the owner who has died without making any will, whether consent of other legal heirs of the family is necessary ?

What are the pros and cons if consent of others is not taken and an affidavit from nominee owner is taken.

No. You should not purchase such flat instead you request the same person to first obtain from all legal heirs the registered release deeds and then enter into transaction. You should also advertise and obtain NOC's or objections. Otherwise it voidable contract

No. One should never do that. First look into all legal heirs. And meet society 's secretary and obtain all information. You can go for search from search clerk also.Please obtain release letter in favour of vendor and the said documents can be registered. Advertise through advocate in two news papers and ask objections if any.