Dear client,
The society may not deny the transfer of 50% ownership to you, as the gift deed is a valid legal document transferring the ownership of the property from your grandfather to you. However, the society may require certain documents and clearances before processing the transfer, such as a no objection certificate from your aunt and payment of any outstanding dues, so it's best to check with the society's rules and regulations on transfer of ownership.
The order of names on the share certificate and sale deed agreement will remain the same unless they are amended through a legal process. Therefore, your aunt's name will continue to appear before yours on the share certificate and sale deed agreement.
Your aunt may challenge the gift deed on various grounds, such as fraud, coercion, undue influence, or lack of capacity of your grandfather to make the gift. However, as long as the gift deed is properly executed and registered, it will be presumed to be valid unless proved otherwise. Your aunt may need to file a legal suit challenging the validity of the gift deed and provide evidence to support her claim.
Your grandfather was the legal owner of his 50% share of the property, and he had the right to gift it to you without the consent of your aunt. However, your aunt may be entitled to claim her share of the property as a co-owner, and she may have legal remedies to enforce her rights, such as partition or sale of the property. It's best to consult a lawyer for specific advice on your situation.