Queries regarding Agreement to Sell (Immovable Property)

I want to sell my flat - in Kolkata The original owner of the property was my grandmother - who died intestate. I am her sole surviving heir - and as such, the property in question has already been Mutated in my name (by the Kolkata Municipal Authority). Present Market Value of the property is about 62 Lacs - as per online valuation report of the Directorate of Registration and Stamp Revenue MY QUERIES ~ 1) According to one Advocate, I SHOULD NOT hand over photocopies of the relevant Documents (Original Deed/ Mutation Certificate etc) to PROSPECTIVE BUYERS - until and unless such buyers pay a token sum - as EARNEST MONEY... Queries ~ --> Is that correct? --> If so, then WHY and HOW will a prospective buyer agree to pay a sum of money - however small - WITHOUT scrutinising the Title Documents of the property, to verify the legal status of the property? --> What will be the DOCUMENT that is generated - against the payment of such an Earnest Money? 2) According to the above-mentioned advocate, an AGREEMENT TO SELL maybe drawn out and signed by both parties AFTER the payment of the Earnest Money - and, such an ATS NEED NOT be REGISTERED - even if the agreement involves an ADVANCE PAYMENT (10%) of the FINAL COVENANCE VALUE... Queries ~ --> Is that correct? Suppose the Buyer pays 6 Lacs as ADVANCE - but then they FAIL to affect the actual SALE and TRANSFER within the stipulated period of the Agreement... In that case, if such clauses are clearly defined within the ATS, will I ACTUALLY be able to FORFEIT the Advance payment - against an UNREGISTERED ATS? --> What will be the Stamp Value required for such an unregistered ATS? --> Which Clause of which Act/Rule OUTLINES the details for such UNREGISTERED ATS of Immovable Property - and the Stamp Duty for the same? 3) According to the Directorate of Registration and Stamp Revenue ONLINE DOCUMENT (https://wbregistration.gov.in/) for "Stamp Duties & Fees" (https://wbregistration.gov.in/) ~ 5 Agreement (a) If relating to sale of immovable property...................... The same as conveyance for market value (No.23) Query~ --> Why and how does the ATS NOT fall under the purview of this category? Thank you for your time!