daughters right to ancestral property

 Hi, I am from Andhra Pradesh…My Grt Grand Father has self acquired  4 houses in 1908 and he was the karta of our joint hindu family.  He died in 1927 and at the time of his death his brothers litigated and called for a division of property through an arbitration, which has decided 2 houses in favor of my grand father and his mother legal heirs to my late Grt Grand Father…now my grand father had 3sons & 3 daughter and he died in 1976 …1^st  daughter was married in 1945 and died soon after deliver 1 g child….2^nd  daughter was married to same groom and she had 1g child & 1b child  she died in 1991…3^rd  daughter surviving got married(now widow) in 1964 is having 2 g child…since the death of her husband my father and his brothers have been taking care of her…now 3 rd daughter(my father’s younger sister) is claiming a right to equal share in the our ancestral property.  However My father and his brother have been assuring her of her old age maintance (give 1 flat and 1 shop as long as she survives) as she is alone now after her 2 daughters marriages…

We also have a open land surrounding one of the houses…which was in our  possession for the last 80year which is not included in the property document when my grt grand father self  acquired it….only house is shown in the schedule of the property…we had a dispute with our neighbor on this land my grand father had legally won it in our favour….

now the said property is still in combined owner ship or undivided condition….now we are proposing to do some construction activity on this property…

I have been going through a lot of legal stuff  regarding daughters right to ancestral property…a lot opinions have been presented…my questions

1. How far she can legal defend her claim?
2. Do the siblings of other 2 daughter have any chance for claim?
3. What is the scenario  “ if my grandfather dies before 40 years” , explain how does this work to this law even though my case  fit in or not?
4. I have read in some article that as per AP property act daughter married after 1993 or 1998 only have equal right in ancestral property and not before that….how far this is holding good in my case?
5. I have also read that their has been a central act in 2005 on this saying equal right…what are the applicability conditions for this act…how does this act hold…does it applies to cases filed after 2005 or division taking place after 2005?
6. Does this 3^rd daughter have right to force my father and his brothers to go for any division…if they drop all their plan to construct / part / etc….and just leave the property as it is…as we are living in this house…?