Tenants rights in redevelopment

Our building was very old and designated as dilapidated by BMC. The BMC had issued 5 notices for evacuation and landlord was not heeding to tenants request for repair. During this time, the landlord sold the building and land to a builder, who is now the owner of the plot and the building. This was not communicated to the tenants, and till date there is no formal or legal communication of the same. Upon insistence of the builder / landlord, all the tenants evacuated the building only on a promise of new flats on ownership basis and a notaried agreement that builder will demolish the building and give us the same carpet area we had earlier and also pay the rent for the duration of time it takes to build the new building. After we evacuated the building was demolished. The builder gave the tenants advance rent for one year, which includes one month of commission. My queries are as follows: 1. Is there any prevailing law which states that the builder has to provide any minimum carpet over and above the current carpet area? Or is the builder liable to pass on some percentage of FSI benefits to tenants? 2. Can the tenants, who wish to buy any additional area over and above the allotted carpet, get a discounted rate per sq. ft.? 3. What are the rules if the tenant possesed two different numbered rooms with two separate rent receipts but a single electric meter? Are they entitled to two different rooms automatically? 4. Can the tenant split the total carpet possessed, and use it against any additional carpet in different rooms, that the tenant is purchasing in the new building being constructed? For example, if the tenant had 200 sq. ft. of existing carpet, and the new rooms are 220 sq. ft., can the tenant split 100 sq. ft. and adjust it against two new rooms by paying for 120 sq. ft. in two different new rooms being built? 7. When should a builder initiate permanent alternative agreement and other documentations with the tenants? Floor plans, allotment letters, etc. 7. Is the builder responsible to pay shifting charges also? Or Only rent? 8. Who should pay stamp duty & registration charges? Are the tenants expected to pay these charges for only additional area being bought or total area of the new flat? What are the charges in percentage for mumbai? Thanks.

You may consult a local lawyer who is fully conversant about the laws relating to the re-development of pagadi/tenanted property and go ahead as per his further advise, because without seeing the terms and conditions agreed between you both, it will be difficult to give opinion to your queries.