Hello Sir,
Below are the replies to your query:
1. As per the provisions of Income Tax Act, at the time of purchase of property, buyer has to deduct the TDS when the he pays to the seller. So, as per the law you have to deduct the TDS for all 4 sellers.
But as you have already deducted and deposited the same in the name of 1 seller then now in that case, you can revise the return to comply with the requirements of law.
*In case you would not prefer to revise the return in that case, interest and penalty can be provided by the Assessing Officer.
2. Children will show the transaction as income from capital gain. And the payment in regard to the same has been received in their mother's account.
Hope you have got answers to all you queries.
Thanks and Regards
Divya Chugh