1. your grandfather was original tenant of the 2 1RK in the old building
2. then there arose certain disputes between landlord and legal heirs of grandfather, post demise of GF
3. the dispute was amicably settled whereby the legal heirs of GF were accepted as tenants
4. the building then goes for redevelopment and landlord signs PAAAs with tenants
5. 301 is by mutual consent of all parties agreed to be allotted to GM and B and 302 is agreed to be allotted to GM and legal heirs of A. Though in consent decree GM, A and B have been accepted as joint tenants
6. in my opinion, so long as the new flat with OC is not handed over to the tenant, the relationship between the parties continues to be that of landlord-tenant
7. this is because the tenant continues to pay the notional rent to the landlord pending allotment of new flat and in lieu of that rent the landlord continues to issue rent receipt to the tenant
8. under law a property which is held on tenancy basis can neither be gifted nor Willed
9. so prior to the allotment of new flats, even if A2 manages to obtain a Will from GM therein bequeathing her share in your flat to A2 - that will be of no consequence - because tenancy rights cannot be Willed
10. similarly a gift deed cannot be made
11. a Will or gift deed can only be made by grandmother in respect of her undivided share in both the new flats only once the new flats are allotted with OC and not prior to that
12. i see no logic in having all three ie GM, Legal heirs of A and B as joint allottees in the PAAAs for the 2 new flats - because there too the GM will have 1/3rd undivided share which as per your apprehension can be Willed or gifted away to A2
13. So unless and until the new flats with OC are allotted, the relationship of landlord tenant will continue and thus the tenant cannot make any Will or gift deed of his/her undivided share in the new flats to be allotted
14. as to the declarations executed by both parties in favour of the other - so long as the owner is alive, his/her legal heirs have no right whatsoever in the property owned by owner and thus any such declaration made by the 'to be legal heirs' giving up their right in the property which they 'may' inherit after demise of owner - is of no consequence and useless
15. so say the GM dies, then B cannot show the declaration executed by legal heirs of A and say that - look you'll had executed this declaration and so now you do not have any right or claim in the half share of GM in 301-
16. the declaration is not at all binding on the legal heirs of A as that was made during the lifetime of GM
17. Had such a declaration been made after demise of GM then it will be binding on the legal heirs of A