GPOA AND SALE DEED

Letters mentioned here as A ,B, C, D and E represent persons mentioned for the ease of understanding. Seller XYZ sold a property to A,B,C, and D in year 1996. A,B,C and D being the co owners with equal rights on property. In year 2006 owner A and B gave registered GPOA (General Power of attorney ) to C for working on behalf of them. Owner A gave a legal notice of cancellation of POA to C in year 2011. Owner (A) transferred the property to his sister (E) as registered gift deed in year 2015. Same changes were made on 7/12 property card in 2017. Since 2017 owner on 7/12 property card are E, B, C and D In 2016 "C" used the POA to make a registered agreement of sale using a forged unregistered Agreement of sale he made in the year 2001 with forged signatures. In June 2019 "C" transferred the property rights of A and B to himself registering a Sale deed document using the cancelled POA and Registered agreement of sale of 2016 , attaching old 7/12 property card having Owners A,B,C and D , whereas the current owners being E, B, C and D. My queries: 1) Is it allowed to use 2 year old 7/12 property card to Register a sale deed ? Any Law governing the same ?, any reference would really help. 2) Is a GPOA holder allowed to transfer property on his own self ? 3) Is the GPOA still valid for Person "C" after the Donor "A"has already transferred the property to "E" ? 4) Is a person allowed to register a unregistered Agreement of sale after 10 years ? Thanks a lot, Regards.