Can we purchase a land?

Hello Respected Lawyers, We are purchasing a 1 acre farm land which is registered/Pani (Karnataka Bhoomi Pani) in Seller name which was given by his Father. Seller Father have 4 son and 2 daughters. All 4 son got 1 acre each a total of 4 acre and one son is selling his 1 acre due to his personal commitment. This was equally shared by his father in 2006. Two sisters expired in the year 2014 and one more sister died in 2018. Now the question is can we purchase this 1 acre land? what litigation can come? How to face and what precaution we need to take before buying or agreement or registration... One more question like to know, is there is any chance whether Sisters daughter/son have rights to question Seller brother or may create concerns on us? If yes as I am a buyer what I have to do? As per Seller, they are not in touch with there two late Sister kids and they are not close now after Sister death and not ready to take their 8+ sisters son/dauhter signatuer who are now aged almost more than 40 to 50 years. Some says different laws and amnendent, it's confusing... Our hindu law is so confusing and keep getting changed.... Please advise and help...