Buying flats is legally valid if the building is only of 4 flats, society can not be formed

This is 50Sqm cidco 12.5℅ land with G+4 structure. Builing seems to be built as per the commencement certificate. Some finishing work is yet to be done, OC is pending. There is a tripartite agreement between CIDCO, original allottee and the builder (A)in 2015. CC is issued in the name of A only. Due to funds shortage, builder A had done registered development agreement with party B with a power of attorney (POA)with 50: 50 sharing of flats (2 flats each). Now developer B wants to sell his share of 2 flats. Upon insisting that total building should be bought by me, both party A and B agreed. Party A has earlier sold 2 flats in the year 2018 with advance of 1.5L to party C but both party B and C have agreed to do the regd. cancellation deed now post refund of the advance amount of 1.5 L. Then all the flats can be sold to me. My bank is worried as CIDCO is not party to the development agreement between A and B to which I answered that all 3 parties like me, party A (tripartite holder) and B (Developer) will sign the regd sale deed. As party A is a party to the sale deed, then it should not be an issue. Second query from bank is as there are only 4 flats, hence society can not be formed. Again, CIDCO is not party to our sale deed, hence CIDCO will not give mortgage NOC to the bank for extending home loan to me. Third, can individual flats be sold to me through 4 separate agreements in which all the partes like A and B will sign? How will be the property transferred to my name in cidco records... Can conveyence deed can be done now. Builder has cidco approved plan for G+4 structure. Request your guidance.