Spes Succession , GPA , Consent and Sale Agreem ent

URGENT REPLY...... Independent house purchased by Mr.X on sale deed in 1980 and Mr.X is having 6 childrens (4 Sisters and 2 Brothers) Mr.X died in the year 1995 and Mr.X wife died in the year 2019. No will written by Mr.X or Mr.X wife or Any registration happened till date. Now Mr.X family given for KHATA CHANGE on 6 children's name at municipality. But issue is most of the sisters stays in USA so they are in India at present, returning to USA this month. KHATA CHANGE will take nearly 45 days. 6 Children's are saying they will make GPA on last brother (who stays in india) he will execute SALE AGREEMENT and Registration process completely. My questions: 1. Both parents are died No Will return by any one of them. Is all 6 members absolute owner of parents property? 2. Can 5 children's make GPA for one of the brother and complete Sale Agreement and Sale Registration Process with purchaser? 3. Should i need to take consent of 6 members individual family members also...? 4. Can i make sale agreement from one of 6 childen's before GPS or After GPA...? 5. Is thr any alternative method for direct transfer of property from 6 children's to Purchaser? 6. I know that, Grand children's will have rights on Grandfather property will same apply here also....? or becuase Grand father purchased on sale deed will it come under Inherited property...? 7. Is i need to take NOC/Consent letter/agreement from Grand childern's of 6 members family....? 8. Can i purchase this property using this method : 5 Children's giving GPA to Brother => Brother => Sale Agreement => Sale Deed Is this process valid in court of law ? if any complication raises in future? 9. From GPA holder can i purchase the property ? if GPA provided by absolute owners. (5 members) 10. Kindly suggest legal procedure to buy above property.