Urgent help - need advice on buying a 22 cents agri land in chennai that has no mother document.

Hello Sir,

I recently visited a 22 cents agricultural land in Chennai and am considering buying it as it is available at a good price. I have already obtained a copy of the land documents from the owner and received a legal opinion. Here are the key facts about the land:

1. The original land was 5 acres, first sold in 1991 by the owner, who created an unapproved layout with several 22 cents land parcels.
2. The current 22 cents I am considering purchasing is from this parcel. There have been two purchase transactions, and the current owner has held the land since 2002 (22 years).
3. I obtained the Encumbrance Certificate (EC) from the TN Government website, covering records from 1988 to date. The land is clear and has a patta under the current owner's name, which I verified online.
4. The Real Problem: According to the land records, the first document was registered in 1991, stating that the original owner was in possession of the land. However, there is no mother document showing how he acquired ownership. Everything starts from 1991, and the ownership before that is unknown. The land has been sold and purchased three times. The current owner assures me there have been no issues in the past 22 years. My lawyer says it is my choice, and given the last 30 years of clean EC, it is highly unlikely any issues will arise.

I am confused and unsure of what to do. My questions are as follows:

1. Is it safe to buy land that has no mother document and only shows transactions from 1991 onwards?
2. Some of my friends mentioned that land records starting from 1965 for any land in Chennai can be found in the "A Register" at the Collector's Office in Chengalpattu. Is it possible to know the history of the land from the Lands Department for the period 1965 to 1991?
3. I spoke to the Owner and he agreed to apply and get an extract of A Register for his land as of 1965. However this will only show who was the owner of the Land in 1965. Assuming that the owner for all these land parcels was Mr. ABC. My lawyer felt that if the land was owned by an individual then its safe to buy because this is an assurance that the land back in 1965 was not a temple property or given by anyone as a Dhana/Gift. If no one has claimed ownership since 2002, its highly unlikely that someone will show-up.
4. Finally, The EC is clean but how do I ensure that this land is not mortgaged by the owner to anyone or the current land does have any cases on it.

Kindly advise. Thank You.