Registration of Chawl which is covered under 33(7) rules.

Hi Team, I am resident of a chawl, which is owned by BMC and currently one builder developing a building for all the tenant of the chwal under 33(7) rules (builder has received CC, LOI, IOD etc and work is in progress). This chawl room is owned by my uncle and now as per our mutual and family discussion, uncle agreed to transfer the property on my father and mother's name. For such settlement Builder is preparing transfer or tenancy right agreement without specifying any consideration (since we are not paying any consideration to uncle) and builder is suggesting that we need to get it registered with the registrar office and need to pay Stamp duty for the same. He has further suggested that after registration it will be proper proof and uncle will not be able to claim it again in near future. However, I heard that for dwelling houses (Chawls and Zhopadpatti) no registration charges and stamp duty required to be paid with the registrar, since stamp duty act does not applies to dwelling houses. Please guide me for the following point: 1. Whether such transfer of tenancy right agreement is required to be registered with the registrar. 2. If the answer for the question 1 above is affirmative then is it advisable to get such agreement registered to avoid future disputes, since the stamp duty and other charges is costing little high. 3. Further, if the answer to question 1 is affirmative, can't we get the benefit of transfer to the related family and thereby we have to pay the stamp duty of 2% at concessional rate. (It has been informed to us that since my mother is not in blood relation to the uncle and hence we will not be able to get the concessional stamp duty of 2%, instead we have to pay stamp duty @6%). 4, whether any other alternate way is possible such as getting the agreement notary with the notary lawyer, will this suffice to prove the ownership of father and mother? Will this be treated as evidence in the eye of the law? Thank you.