A. As per the state amendment introduced by the Karnataka in 1994, if the women got the marriage before 1994, she will not have any share over the property. But in the year 2005, the Hindu Succession Act was amended and overruled the state amendments. So women can claim a share over the ancestral or joint family property as coparceners by birth.
B. Mere the SBI given green signal over the property is not perfect title, usually the bank will ponder over the interest, create a charge over the property and the bank has obtained all securities from the customer at the time of sanction loan. The third party claim's clause is a general clause in all agreements. Even though not mentioned this clause that the owners have a bounden duty to resolve the matter as per law
C. In your case, this matter would be settled out of the court by offering some flats to that lady by the builder side and the same damages should be recover the same from the previous land owners under the indemnity clause, In Bangalore, this is normal practice going on and also settled by giving consideration or offering the flats.
D. You can approach the builder to refund the amount or insist to resolve the matter by offering some flats to that lady or approach the Consumer Forum to resolve this matter.