Buying a pent-house form First owner with EC, tax receipts.

Hi Sir, I am planning to buy a pent-house in Ganga Parameshwari nagar, duo layout, Bilekahalli. It comes under the land owners share. I need details If I could proceed with buying this flat. The owner has paid tax on this property till 2016 and having encumberance certificate[EC] etc., The apartment is constructed on a BDA site allotted by Vijaya Bank to the employees[Land-owner former employee of Vijaya Bank]. Please let me know about the complete risks and advantages or disadvantages involved in buying this property. And if i could proceed with buying and not face any issues in future with this property legally or otherwise. Private banks like DHFL and PNB[punjab national bank] are ready to provide loan for this property. What are the various documents, steps and other things to look out for before i proceed? Also let me know how I could genuinely assess the net worth of this property. I checked for the current price/sqft in this area as well as selling price in nearby apartments in online forums etc., Is there any other better way of getting the right details fr this,. Please let me know as well. Thanks for your time. Regards, Kavitha A