Agriculture Family Certificate and Family Tree Karnataka

My grandfather had agriculture land in his name 40-50 yrs back in Bangalore and now they have been converted as residential layouts and houses.But we have the RTC which is in my grandfathers name. Now I am planning to buy agriculture land in my mother's name as I am not eligible to buy.At present my mother doesnt have RTC in her name nor she owns any agri lands.Since my grandpa had agriculture lands 3-4 decades ago, my mom is eligible to buy agri land, hence buying in her name. Now i need to get "Agriculture Family Certificate" from Tahsildar in my mothers name so that I can use it to buy agri land. Can you let me know whether my mother is eligible to buy agri land using agriculture family certificate ? Also we need Family Tree of my mothers family which consists of her 3 brothers and 1 sister.Since we both are not in good terms , it is difficult for us to approach them and ask for any signature which is needed for family tree.We know the names of all the family members and their children.Can we make a family tree and get it affidavit by a notary and then submit it to tahsildar / DC office to get agriculture family certficate or do we have to get a certfied copy of the family certificate from Revenue officer and then submit it to tahsildar office to get agriculture family certficate ? One last Question : Using agriculture family certificate, can my mother buy agri land or will there be any issues later if this violates article 79(A) and 79 (B) Your help is much appreciated